The New York Times had an article about German homes that require little energy to heat:
http://www.nytimes.com/2008/12/27/world/europe/27house.html?_r=1&partner=rss&emc=rss
Interestingly the author concludes that american builders are not doing this type of construction and that proper insulation and HRv’s are not available………..
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Very interesting read.
I intend to read the links contained when I have a moment to do so .
So what sort of construction is it? NYT is not an open site.
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NYT has free registration. Here's the opening section."DARMSTADT, Germany — From the outside, there is nothing unusual about the stylish new gray and orange row houses in the Kranichstein District, with wreaths on the doors and Christmas lights twinkling through a freezing drizzle. But these houses are part of a revolution in building design: There are no drafts, no cold tile floors, no snuggling under blankets until the furnace kicks in. There is, in fact, no furnace.In Berthold Kaufmann’s home, there is, to be fair, one radiator for emergency backup in the living room — but it is not in use. Even on the coldest nights in central Germany, Mr. Kaufmann’s new “passive house†and others of this design get all the heat and hot water they need from the amount of energy that would be needed to run a hair dryer.“You don’t think about temperature — the house just adjusts,†said Mr. Kaufmann, watching his 2-year-old daughter, dressed in a T-shirt, tuck into her sausage in the spacious living room, whose glass doors open to a patio. His new home uses about one-twentieth the heating energy of his parents’ home of roughly the same size, he said.Architects in many countries, in attempts to meet new energy efficiency standards like the Leadership in Environmental and Energy Design standard in the United States, are designing homes with better insulation and high-efficiency appliances, as well as tapping into alternative sources of power, like solar panels and wind turbines.'Man who say it cannot be done should not interrupt man doing it' ~ Chinese proverb
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But they insist on setting cookies which I refuse. Even that section doesn't really say what specific kind of construction this is, just good insulation and some passive solar....claiming that Americans don't do it just ain't so.
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
“You don’t think about temperature — the house just adjusts,†said Mr. Kaufmann, watching his 2-year-old daughter, dressed in a T-shirt, tuck into her sausage in the spacious living room, whose glass doors open to a patio. His new home uses about one-twentieth the heating energy of his parents’ home of roughly the same size, he said.
Sure, it's easy to keep warm if you dress in a sausage ;-)
Germany has been ahead of the US in building technology for some time. Their Bau-Biologie movement has pioneered healthy homes, and now their Passiv-Haus is leading the way toward Zero-Net Energy.
But Zero-Net comes with a financial price and requires some pretty sophisticated technologies, such as super windows.
If I took my Energy Star 5+ modified Larsen Truss house (at 2000 SF in an 8500 HDD climate), added a 70% efficient HRV, increased the square footage of south glazing to 12% of floor area and made them all R-5.6 with 0.40 SHGC (about the best currently available), it would become a Net-Zero house.
But my clientelle couldn't afford to build it, so I compromise on a house (HERS Rating of 46) that uses 58% as much operating energy (heating, hot water, cooling, electric) as a baseline cold-climate Energy Star home, 46% of the operating energy of an IRC Energy Code house, and 35% of that of a typical house.
There's a problem with high incremental costs and diminishing returns when going to extremes.
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
Edited 12/27/2008 1:43 pm ET by Riversong
I can't remember if you've ever mentioned the windows you use...
I can't remember if you've ever mentioned the windows you use...
I've been using Pella Proline casement, double-hung, and fixed windows, with their standard LowE² glazing.
Unfortunately, their double-coated LowE glass has less SHGC than I would like for a passive solar design (0.41). If I could find a similarly well-constructed window with a higher SHGC (perhaps the Canadian pul-truded fiberglass units), I would get better solar performance.
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
Sure, it's easy to keep warm if you dress in a sausage ;-)
Robert, to be fair to Passive House... I think that they are promoting air tightness...not vapor tightness. Much like your homes of 0.1 ACH nat.
You are possibly beyond their standard for insulation and thermal bridging.
The Passive Haus windows are expensive and hard to cost justify.
Your ventilation strategy is probably the next best thing to an HRV.
But ventilation is your weakest link. Perhaps if you ramped back a little on your r-value than you could afford better ventilation.
I plan to increase insulation in my next house and consider an HRV.
Edited 12/28/2008 1:53 pm by homedesign
Robert, to be fair to Passive House... I think that they are promoting air tightness...not vapor tightness.
Absolutely - I didn't suggest otherwise. A basic principle of BauBiologie is that the house be able to breathe.
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
The fundamental problem I have with your approach is it's simply a modification of typical stick building.. Rather than a new leap forward.
Let me discard my preferance for a moment and propose a hypothetical using my preferance as a base to depart from.
What I appreciate about SIP's and ICF's is they are an intergal system whereby strength and insulation is combined as a unit rather than added to a wall system..
Imagine something like a SIP or ICF without the ingrediants that you find so distasteful.
Further imagine that such a unit could be highly moble. The average American family moves every 5 years.
Without the limitations and danger of moble home parks.. Something along the line of Container ships containers..
The fundamental problem I have with your approach is it's simply a modification of typical stick building.. Rather than a new leap forward.
The problem with most "leaps" forward is that we have a decided tendency to leap before we look. If we thoughtfully considered new technologies before bringing them to market, 99% of them would be abandoned. This is how the Amish operate, and as a result they realize far greater efficiencies in their farming than American agri-business.
We Americans are idolatrous about "progress", and have very little respect for the value of traditional technologies.
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
Reading some of the links from NYT:
http://www.nabihtahanarchitect.com/show_content.php?sid=15&language=en
http://en.wikipedia.org/wiki/Passive_house
They can't get your Goat if you don't tell them where it is hidden.
""Construction ProjectsSmith House, 2002-2003German-born Katrin Klingenberg, founder of e-co lab, completed a 1,200 square foot home in Urbana, Ill., in 2003. Her goal was to demonstrate that stringent Passive House energy standards could be met in the severe climate of Central Illinois. The project has succeeded, inspiring the ongoing construction and research efforts of e-co lab.Applying computer modeling, Klingenberg implemented several, but not all, of the many techniques, systems and materials that can be used to reduce energy load the required 90 percent. Among them:•Superinsulation (total R value of 56) and supertight thermal envelope--thermal bridges are minimized.•Orientation that maximizes passive solar heating in winter, cooling in summer.•Triple-glazed windows.•100-foot long earth-tube air intake for pre-heating and -cooling.•Heat Recovery Ventilation (HRV) that recovers heat from exhaust air, and ensures constant outdoor air ventilation for excellent indoor air quality.•Instantaneous electric water heater.Read about the Smith House in this Energy Design Update Article.See below for basic specifications and links to suppliers.LocationUrbana, ILArea1,200 square feet, with loftFoundationConcrete-block frost wallFoundation perimeter insulation6 inches of expanded polystyrene (R-24)Under-slab insulation14 inches of expanded polystyrene (R-56)Wall framingWall framing Vertical 12-inch TJIs(Trus Joist I-Joists)Wall insulation12 inches blown-in fiberglass plus 4 inches of exterior rigid polystyrene (R-60)Roof framing16-inch TJIs I-Joists) with vent channels above the sheathingRoof insulation16 inches of blown-in fiberglass (R-60)WindowsThermotech windows with triple-pane, argon-filled, low-e glazingVentilation systemWestaflexWAC 250 heat-recovery ventilatorHeating systemElectric resistance element in the HRVDomestic hot water systemStiebel Eltron instantaneous electric water heater
They can't get your Goat if you don't tell them where it is hidden.
http://www.passivehouse.us/passiveHouse/Articles.html
They can't get your Goat if you don't tell them where it is hidden.
Dovetail,
Here is another link that I have found useful
http://www.passivhaustagung.de/Passive_House_E/PassiveHouse_directory.html
I think that many of us could learn a thing or two by studying what the are doing.
Of course these are very extreme homes...extremely airtight, extremely well insulated, well ventilated and thermal bridge free.
And perhaps extremely ugly.
We can build cars almost as well as the Germans.. why not houses.
Thanks, that is a good link.
They can't get your Goat if you don't tell them where it is hidden.
Good link showing the German approach.The concepts are the same as those promoted for years in this country by a small group of innovative builders. I believe the products such as high performance windows and insulated panels are available in most population centers and HRV technology has been around for 20+ years. One thing I was reminded of from the NYT article (and common sense) is the simplicity of design the Passive Homes employ. It's not your 5200 ft. sq. house with lots of corners and architectural elements for the sake of "beauty". It's much easier to prevent thermal bridging without a multitude of corners and things like dormers and bay windows, etc. Also, with many homes being built today for 2 persons ranging in the 1200-2000 ft. sq.per person range, the likelihood that internal gains will make much of a contribution to heating is slim compared to those Passive houses.
with lots of corners and architectural elements for the sake of "beauty". It's much easier to prevent thermal bridging without a multitude of corners and things like dormers and bay windows, etc.
Which is actually two very different things.
First off, there are very few licensed architects in residential design--there are far too many 'clever' people hiring up minimum-wage kids with CAD backrounds to pound out 3-page house plans 8, 9 hours a day. Those shops work almost exclusively in 2d, so, the plan is whatever it is, corners, notches, wings not-quite aligned; every design failure imaginable. The roofs over these things give them away--hanging valleys, hanging ridges, mis-matched hips and gables (or, my fave, a 18"-24" long ridge 16-18' about plate height where the hips could have almost intersected, which then has 3-4 mushroom vents to make "output").
Dormers and bay, on the other hand, done properly, allow smaller rooms to be larger, to be more usefull, to be better for the occupants. And all with out adding 10 or 20 or 30% to the overall floorplan. That is, unless the unlettered just stab them on willy-nilly 'cause the sales staff heard a person in the model house comment on the lack.
But, I'm biased in this; others differ.
(That spiffy German house would cost thousands to run down here in my tropical climate--passive design is very much defined by latitude, and very narrowly at that.)
Occupational hazard of my occupation not being around (sorry Bubba)
Edited 12/27/2008 2:20 pm by CapnMac
I agree that these homes are limited by there latitude. I work and have lived in the lower deserts of Calif where day time highs are 110 plus and it can be 100 degrees at 10PM during the summer.
I would think that ICF's could be a great building system in the desert.. the need for heat rejection would be met by the insulation on the outside of the ICF and the need for cool air retention would be met by the insulation on the inside while using the thermal mass to moderate either extreme..
I've been in tichkwalled adobe houses and the thermal mass alone has a cooling effect in desert climates during that day and a warming effect at night when temps drop so severely..
>> Dormers and bay, on the other hand, done properly, allow smaller rooms to be larger, to be more usefull, to be better for the occupants.That sounds like the "not so big house" concept.
To do it right, you really have to have some vision of the home as a social space. Dormers and bays are not just visual tricks to make a little house look big. A dormer can be a space to sleep in. So how big does the bed need to be? A bay might accommodate an eating nook, or a desk. So how low can the windows go before the desk space is compromised? If you're sitting 2 feet from the window at a desk, how big does the window really need to be anyway, for a personal view?I live in a beautiful, smallish house designed by a licensed architect. Trouble is, he was a young guy right out of school, with no family. The little nooks look great and helped sell the house. But, they are just a tad too small to be functional for a Christmas tree, or to extend the table at Thanksgiving.The house design has to be approached holistically, as more than an engineering problem. Otherwise people won't be comfortable in it. They'll be chasing after additional space instead of using the space they have, efficiently.
The house design has to be approached holistically, as more than an engineering problem. Otherwise people won't be comfortable in it. They'll be chasing after additional space instead of using the space they have, efficiently.
That is an elegant, and concise, summation of "why" more people need skilled designers (as opposed to 'trained' drafters) in residential work.
But, so many 'grow up' in 8 foor tall sheetrocked, white-on-white-on-white 2-400sf boxes into which ever more stuff is merely jammed against whatever remaining wall space is available, that the experience of design is nearly foriegn to all.
Does that mean all building designers ought be forced through the meat grinder of college? Only if you ask AIA and NCARB (with some knowing complicity with legislators and licensing agencies). To put a fine point on it though, I do feel some education is good for designers (meaning some definable minimums). I'm just presently in a mixed bag of emotions about the restraint-of-trade aspects about how the design side of things work.
One of the key things needed in energy efficiency, let alone in smart building, is to unify the way we educate designers. There is only so much a builder can do to "fix" a flawed design. Which means we have to move the customer base to where they want better design. And vast tract-build NAHB subdivisions of mediocre designs, but 10% or 15% "more green" houses will not really do that. Until TB, PH, the rest of the nationals have to start using real design professionals, all we will see are more built-for-speed Yugo-houses in vast, wasteful sprawls.
And, that's where the car analogy fails. A Yugo that falls apart before a person's eyes, is clearly less-good than a "decent" junker. But, given the EE in even the crummy tract houses, can we really "afford" hundreds of acres of "junkers"?Occupational hazard of my occupation not being around (sorry Bubba)
I am repeating my favorite PassivHaus link below and one of my favorite illustrations. It takes a while to follow the tree of links that are offered at the site. Wolfgang even has a Lstiburek style sense of humor.
Yep, those earthtubes are a bad idea and we may not be ready to pay for windows like theirs and the architecture is too bland....but just look at what they are doing right!
I went out and bought a coffee thermos after seeing the photo below.
So simple .. so obvious .. Almost FREE ENERGY
http://www.passivhaustagung.de/Passive_House_E/PassiveHouse_directory.html
View Image
The figure illustrates the basic principles of increased energy efficiency. It shows why energy efficiency can substitute energy:The service needed here is to keep coffee hot. That can be done by consuming energy (right hand, hot plate), or by not allowing for heat losses from the beginning (left hand, thermos flask). A very small heat loss is still there, of course - but it is negligible. Therefore the hot plate can be left out completely.
Edited 12/28/2008 6:49 am by homedesign
We build cars almost as well as the Germans, I'm sorry that's too much of a stretch.
No one can deny the Germans are brillant engineers.. the very est of our offerings are an extremely poor second and most aren't that good..
I don't say that with glee, rather reluctance to admit my countries weakness.
However Americans have a lot of potential to become the energy efficency leaders if we will simply stop building model T houses.. Today's houses differ only slightly in detail from homes contructed well over 100 years ago. Insulation is an add on approach rather than an intergal approach. The sole exceptions I see is SIP's and ICF's.
We build cars almost as well as the Germans, I'm sorry that's too much of a stretch.
Frenchy .. you are right.. I was trying to be kind.
Not all of us are building houses the way they did 100 years ago.
100 years ago we did not know what an air barrier was.
We did not talk about thermal bridges and energy recovery.
It is not just the materials its how you put them together.
I know there are some screwed up SIP houses out there and there is probably a way to screw up an ICF house.
We now know that if you trap water in a dead valley between a dormer and a turret.. then you may be asking for trouble. SIPS don't build houses..people do.
I suppose if we built the frame of a house in 1880 it wouldn't be wildly differant from that same house frame today.
Oh sure built easier because of nail guns, Skilsaws, and telehandlers etc.. but the carpenters of 1880 would take maybe a week to get up to speed with todays' carpenters..
The rest is simply added onto an old fashioned model T type of construction.. Insulation, vapor barriers, plywood etc. etc.. etc. ..
We divert from the main thrust of the discussion when we discuss failures of proven systems due to poor technique etc..
True our furnaces are no longer coal units that need to be stoked and ash hauled etc.. Our bathrooms are far more complex and even indoors compared to back then, but no big leaps forward like automobles have made in the past 100 years..
but no big leaps forward like automobles have made in the past 100 years..
Today's internal combustion engine and drivetrain are essentially the same as the Model T, except that the US fleet average fuel mileage is worse!
Diesel, bio-diesel and electric cars are a hundred years old.
What has "advanced" in cars is mostly the complication.
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
if you trap water in a dead valley between a dormer and a turret.. then you may be asking for trouble
Just to let you know your humor wasn't missed.
Just to let you know your humor wasn't missed.
J, I considerd drawing a red circle around it.. but its better this way.
However Americans have a lot of potential to become the energy efficency leaders if we will simply stop building model T houses.. Today's houses differ only slightly in detail from homes contructed well over 100 years ago. Insulation is an add on approach rather than an intergal approach. The sole exceptions I see is SIP's and ICF's.
Americans will become leaders in efficiency only when we're willing to live as modestly as Europeans - small homes, small cars, less stuff.
What you continue to call the "model T", however, are wood-frame houses such as I have been building, which with only slight modifications would meet PassivHaus standards.
Except in retrofits, insulation is not an "add on" but part of an integrated design that meets both occupant and global needs - but only if it's "green" natural material.
The only reason you see a "sole exception" is that you've chosen to narrow your perspective to one building system that has significant environmental drawbacks.
Open your eyes, Frenchy. There's lots more to choose from than plastic and concrete.
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
Hmmm... based on that description it sounds like someone on this site has implemented quite a few of those principles as well. Maybe he should get a NYT article.
Dovetail
To read the article in FHB from a year ago about Ms. Klingenberg use this link
http://forums.taunton.com/tp-breaktime/messages?msg=102383.1
in our discussion about superinsulated houses.
Rich
hard to believe all that costs only 7% more. Maybe someone is bending the numbers
hard to believe all that costs only 7% more. Maybe someone is bending the numbers
Is that what they're claiming for a PassivHaus? It does seem low.
But it might not be too far off, since I've calculated that my superinsulated homes cost about 5% more than an energy-code minimum house.
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
hey.... we do know they are talking about eating sausage, not dressing like one,..... right ?Mike Hussein Smith Rhode Island : Design / Build / Repair / Restore
hey.... we do know they are talking about eating sausage, not dressing like one,..... right ?
Not if you believe the NYT.
From http://forums.taunton.com/tp-breaktime/messages?msg=114460.4<!----><!----><!---->
"Mr. Kaufmann, watching his 2-year-old daughter, dressed in a T-shirt, tuck into her sausage in the spacious living room..."
<!----> <!---->
<!----> <!---->
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
tuck into is a euphemism for "eating" something
<<<<n.
The act of tucking.
A flattened pleat or fold, especially a very narrow one stitched in place.
Nautical. The part of a ship's hull under the stern where the ends of the bottom planks come together.
Sports.
A bodily position used in some sports, such as diving, in which the knees are bent and the thighs are drawn close to the chest, with the hands often clasped around the shins.
A position in skiing in which the skier squats while holding the poles parallel to the ground and under the arms.
Chiefly British. Food, especially sweets and pastry.
phrasal verbs:
tuck away or into
Informal.
To consume (food) heartily.Mike Hussein Smith Rhode Island : Design / Build / Repair / Restore
tuck into is a euphemism for "eating" something
But this is a German story, and tucker is British.
At one point, the most popular TV show in Australia was "Bush Tuckerman". It followed the adventures of a military officer who was assigned to train the troops in survival in the bush.
A camera team followed him around as he dug grubs out of stumps, caught fish by hand and ate them raw, clawed up roots and made a plastic tarp still to capture water vapor for drinking.
I saw a few episodes. Bush tucker. Better than German sausage.
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
hey.... we do know they are talking about eating sausage, not dressing like one,..... right ?
Mike,
I did a mind-jump myself...I thought we were talking about enclosures.
I thought the sausage reference had something to do with a comment that Robert made last spring concerning Passive House.
102383.40
But building hermetically-sealed homes which are livable only with "artificial respiration" is so antithetical to the way nature works and we evolved as living creatures as to be absurd. I was atttempting to highlight the absurdity.
it was an interesting article but not especially well written... lot's of misdirection and missing detailMike Hussein Smith Rhode Island : Design / Build / Repair / Restore
I don't dispute the article doesn't cover the story or details real well, but if you visit the NYT web site RIGHT NOW you'll see that story is their #1 emailed story. If that doesn't tell us something about the latent interest in low-energy (hi-performance) housing........I believe there is a window of opportunity opening (no pun) that will permit a growth in constructing comfortable quality homes. There has been an interest in "solar" homes for decades. The product has not been there for the masses or even for the discerning home buyer that isn't looking for an architect to design their home. They expect to be able to buy one from their local builder. Some of the builders who haunt this website may be/are exceptions to the rule. But look at the hundreds or thousands of homes that are being boarded up right now from the effects of the housing bubble. Are they any different from the SUV glut? Low performers, overpriced, expensive to own, lack of attention to the meaningful details, poorly designed and executed. Not all are, but you know what these subdivisions are like in general.So, it seems, people that read the Times are curious about the european products in housing like they are about european cars.
I find it interesting that so many can extend themselves and pay a premium for a Prius, in order to make a political statement and show themselves as being green, but when it comes to their housing, cannot pursue that any further than including a few "green" products into their new home.
I guess it is because the passive solar house thing is really only viable as a "green" (meaning that it uses far less energy) solution, if you live in the latitude band across the US where there exists a significant heating season.
View Image
"A stripe is just as real as a dadgummed flower."
Gene Davis 1920-1985
I guess it is because the passive solar house thing is really only viable as a "green" (meaning that it uses far less energy) solution, if you live in the latitude band across the US where there exists a significant heating season.
Gene,
First ..the word solar is not part of the Passive House name.
You can add solar if you live in a heating climate or you can AVOID solar if you live in a cooling climate.
PassivHaus works from Sweden to Roma.
We can design passive without solar.
We can design passive without solar.
Some can, but, here in my majority cooling, majority dehumidifying, climate, insolation is an ongoing concern.
Sure, a person could dig a hole in the ground, and use earth for insulation and mass. The problem with that is that natural light is a needful human thing. it's also free, and has no EE in it (other than the insolation issues).
And, the pervasive local humidity can really "resist" passive intervention. yet, it remains a design dilemma most of the year.
But, go a mere 3 degrees of latitude north, and it's a completelyt differnt climat regime (if still majority cooling). Go 5 to 10 degrees of longitude, nad it can be a different set of design constraints yet again. Seguin and uvalde are only about 1 hour apart, and almost the same latitude, yet Uvalde has a much drier climate, one close to ideal for sun-shaded passive design. Similar conditions apply to Austin and San Antonio--other than an altitude difference. Passive design in San Antonio not only has to cope with a wide temperature range, but rainfalls that cause localized brief flooding (as some "earth sheltered" designs learned the hard way.
But, then again, Texas is 60 milen north to south and 800 miles east to west--there's not just one solution for the State.
Occupational hazard of my occupation not being around (sorry Bubba)
Captain,
Are you assuming that passive design has to be net zero?
My interpretation is that it need only be extremely low energy.
here are some words from the Passive House site:
The Passive House is not an energy performance standard, but a concept to achive highest thermal comfort conditions on low total costs - this is the correct definition.............................................
This is a purely functional definition. It does not need any numerical value and it is independend of climate.
Edited 12/28/2008 4:36 pm by homedesign
Are you assuming that passive design has to be net zero?
No. That's a nice benefit if you can reach it.
No, my assertion had to do with passive being able to discard solar considerations. Solar considerations are an ongoing aspect of passive designs in my climate region. Given the need for dehumidification through the year, it's hard to get to net zero, the mechanical requirements tend to prevent it.
Today, i'd like some insolation gain; yesterday, not so much.
Indoor mass would be handy, too.Occupational hazard of my occupation not being around (sorry Bubba)
The German example is obviously not applicable to all of american climates, just as it is not applicable to all european climates. Nobody in Greece or southern Italy would build to those standards. But, that doesn't mean those in a heating-dominant climate should discount their methods. Sure, germany gets it's share of warm summers as do our northern climate zones. "Appropriate Technology" is a concept long held by folks that have been rallying behind the better construction of homes since the oil shocks of the 70's and 80's: do the "right thing right". Some would say we have been doing the "wrong thing wrong" long enough. But to build the passive house (northern-style) in, say, Dade County FLA, would be doing the "right thing wrong". Instead, the better way would be to address the cost and comfort issues of cooling, humidity, DHW, etc. by the use of appropriate technology. Shading and internal gains and wind are most certainly important.It's easy for us northerners to be so absorbed in solving our problems that we look right past those of our brethren in the south!
I need some help understanding heat exchangers. With the German passive houses, they are using a heat exchanger to extract what heat there is in the outside air, then bringing that heat into the house. In warm climates (or during the summer season), isn't it also possible to use a heat exchanger to bring cool air into the house?********************************************************
"It is what we learn after we think we know it all, that counts."
John Wooden 1910-
not really.... they are using the heat exchnger , probably a by-pass type , to have the inside air being expelled ,used to heat the outside air comming in...
if it were 100 % efficient ( which it isn't ), there would still be a loss
eg : 10 deg outside air vs. 70 deg inside air would result in a net of 40 deg air... but it isn't 100 % efficient... so the net will be lower, like say 30 deg
this 30 deg air then has to be heated to the comfort level of the interior ( 65 - 70 )
the alternative is to use no heat exchanger, expell 70 deg air, introduce 10 deg air and heat that up to the comfort level.... the law of conservation of energy is, alas, still immutible (sic )Mike Hussein Smith Rhode Island : Design / Build / Repair / Restore
Mike,
With a counter current (or flow) heat exchanger the assumption that the max temp would be an average of the two input temps is incorrect. It does sound counterintuitive, but the link below shows how it works.
http://www.engineersedge.com/heat_exchanger/counter_flow.htm
John
thanks.... but that is one confusing diagramgot links to any others ?Mike Hussein Smith Rhode Island : Design / Build / Repair / Restore
You're right, it isn't very straightforward. Here is a link to a wikipedia article comparing the countercurrent results with the concurrent result. Hope it helps.
http://en.wikipedia.org/wiki/Countercurrent_exchange
John
PS As I was looking for info on this I came across quite a few articles about how this principle occurs in the circulatory system of many animals. Interesting how much we can learn from nature!
i wonder what this means in terms of a practical application of an HRV<<<Countercurrent Flow - By contrast, when the two flows move in opposite directions, the system can maintain a nearly constant gradient between the two flows over their entire length. With a sufficiently long length and a sufficiently low flow rate this can result in almost all of the property being transferred. However, note that nearly complete transfer is only possible if the two flows are, in some sense, "equal". If we are talking about mass transfer, then this means equal flowrates of solvent or solution, depending on how the concentrations are expressed. For heat transfer, then the product of the average specific heat capacity (on a mass basis, averaged over the temperature range involved) and the mass flow rate must be the same for each stream. If the two flows are not equal (for example if heat is being transferred from water to air or vice-versa), then conservation of mass or energy requires that the streams leave with different concentrations or temperatures than those indicated in the diagram.>>>>>""""with a sufficiently long length and a sufficiently low flow rate"""""given the example of 10 deg outside air and 70 deg inside air what is the actual net temp from the actual HRV ?do you know ?Mike Hussein Smith Rhode Island : Design / Build / Repair / Restore
I don't know the temperatures, and have not been able to find the specific answer to that question. But in looking for it, I am consistently running across efficience numbers of 70% to 90% for the amount of heat recovered from the outgoing stream. I would guess someone who is a lot more familiar than I am with this subject should be able to compute the temperatures.
John
The coolest example of heat recovery in nature is the tuna. The tuna recovers a huge amount of the heat in it's blood as the blood flows through it's gills, when it picks up oxygen from very cold water.
An HRV is another example of biomimickry.
I can't imagine an energy efficient house without an HRV.
Andrew
I can't imagine an energy efficient house without an HRV.
An HRV is only one stategy to reduce heating (or cooling) loads. And it's a mechanical one that requires an installation cost, an operating cost, ongoing maintenance cost (though, admitedly, those are relatively small), and an eventual replacement cost. So all those costs must be weighed against the benefits.
None of the super-efficient homes I've built have had HRVs. This is in part because the design program was for a very low-tech and low-initial-cost approach that would also entail low operating costs.
Because my super-insulated homes have such a low heat load (~1.4 btu/sf·dd), and because they are built with non-toxic materials for non-toxic occupants require only a minimal 0.25 ACH, the marginal benefit of an HRV is questionable.
Would it improve their efficiency? Absolutely, as would super-windows - for a price.
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
you do use an hrv...... since your houses are so tight, and so well insulated...
your wood burning heat sources require outside air for combustion.... which is then consumed , and sent up the chimney or whatever exhaust system the woodburner uses
the woodburner is acting like a low efficiency hrv..... except that it costs more than an hrvMike Hussein Smith Rhode Island : Design / Build / Repair / Restore
you do use an hrv...... since your houses are so tight, and so well insulated...
I've described my system many times on this forum. I use an exhaust-only ventilation system, using high-efficiency bath fans on timers or dehumidistats, with passive make-up inlets in bedrooms and living spaces. This meets the Energy Star standards here in VT. And it met the Energy-Crafted Home standards in MA.
your wood burning heat sources require outside air for combustion.... which is then consumed , and sent up the chimney or whatever exhaust system the woodburner uses
The woodstoves have dedicated combustion air inlets, either close-coupled or direct-coupled to the stoves.
the woodburner is acting like a low efficiency hrv..... except that it costs more than an hrv
A woodstove would be a zero-efficiency HRV, since it would draw unheated air from the outside if there is not a dedicated supply.
But a woodstove can also serve as a whole-house exhaust fan by depressurizing the conditioned space and helping to draw fresh air in through the dedicated inlets. In this way, it's a "free" air exhaust system, if it's being used for heat.
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
PS As I was looking for info on this I came across quite a few articles about how this principle occurs in the circulatory system of many animals. Interesting how much we can learn from nature!
Dr John, I agree.
I think that Riversongs ventilation strategy ..... intake valves in bedrooms and living areas coupled with timed exhaust fans(shipped from overseas) is a good place to start...very simple ... seems safe... the homeowner(the guy who lights fires inside) can close the valves if they choose.With most homes when an exhaust fan turns on it is a mystery where the makeup air is going to come from... so intentional openings are good.If you want to conserve more energy..why not look at mamals...Concerning breathing.....The human air intake is very near to the air exhaust( intentional openings)Seems counterintuitive? Perhaps it is the best way to conserve the energy?The ERVEnergy recovery does not have to be complicated.It is essential to somehow route exhaust air "past" the intake air? as we humans do.How would the tuna do it? How would Dean Kamen design it?
I think Robert is right about our skin and how it should be vapor permeable...but I think he is still dragging his feet on the significance of energy recovery.
good point but don't forget the sardine input the tuna needs to make it's system functionMike Hussein Smith Rhode Island : Design / Build / Repair / Restore
good point
but don't forget the sardine input the tuna needs to make it's system function
Yes, we may always need sardines..just not so many
good point
but don't forget the sardine input the tuna needs to make it's system function
Yes, we may always need sardines..just not so many
Great point. That's why heat recovery is so sensible. The tuna/house would need more sardines/energy if it didn't employ a heat recovery strategy.
The suggestion, in a couple of posts, that HRVs are complicated and an unnecessary expense has not been my experience. The ductwork is pretty straightforward, a reasonably sized house shouldn't need ducts any bigger than six inch round duct. And HRV's as an HVAC component are pretty inexpensive, and likely to be cheaper with greater adoption by the building community.
I can understand not bothering with an HRV in a superinsulated house, provided their is some sort of ventilation occurring, and where the source of energy for make up heat is free (wood from the home-owners wood-lot). But when you have to pay for your energy I can't see why you wouldn't install an HRV.
This past summer the leaders of the G7 countires, Bush among them, agreed to a statement that their countires would reduce GHG emissions by 50 percent by 2050. This GHG reduction goal represents a huge reduction in available energy from fossil fuels. The only substantial, and least expensive, way that this loss of available energy can be made up is to not need it in the first place. That's why the Passive House design philosophy, with it's HRV and very good windows (more expensive) seems to me to be the best bet when it comes to building houses that are ready for a drastically different future.
The house built today will certainly be around in 2050.
Andrew
Great point. That's why heat recovery is so sensible.
energy recovery is cool, sensible and latent ;0)
Thanks for the pun. : )Happy New Year!!!P.S. Just to be sure I got it I had to check the definitions of sensible and latent. : )heat flux – the transport of heat across a surface. latent – flux of heat from the Earth's surface to the atmosphere from evaporation of water at the surface and subsequent condensation of water vapor sensible – flux of heat from the Earth’s surface that is transported via conduction and/or convection. Sensible heat is the product of the body's mass, its specific heat capacity, and its temperature above a reference temperature.from... http://www.geo.utexas.edu/courses/476K/GLOSS_07.htm
energy recovery is cool, sensible and latent
Not in a super-tight house. Latent heat recovery means recovery of moisture. The primary function of ventilation in a tight house is to eliminate the normal moisture produced by occupants and occupant behavior.
Using an ERV would require the simultaneous use of a dehumidifier, which would consume more energy than is recovered through enthalpy transfer.
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
energy recovery is cool, sensible and latent
Not in a super-tight house. Latent heat recovery means recovery of moisture. The primary function of ventilation in a tight house is to eliminate the normal moisture produced by occupants and occupant behavior.
Using an ERV would require the simultaneous use of a dehumidifier, which would consume more energy than is recovered through enthalpy transfer.
Robert, Are you being a "climatist" again?
There is more than one season....and more than one climate.
Maybe exchange is a better term than recovery.
Sometimes vapor content is greater outside than inside.
Heat exchange is probably more practical than vapor exchange.
I agree that in a tight house we do not need to add vapor...we need to reduce vapor.
In a tight well insulated house the heating season gets shorter.
Does the cooling season become longer?
Edited 1/1/2009 6:13 am by homedesign
In a tight well insulated house the heating season gets shorter. Does the cooling season become longer?
Both season become shorter, which means that the year must then be shorter and you will die sooner ;-)
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
Reposting a Riversong post from the other passive house thread
It's really pretty simple, but the devil's in the details (such as using as-built R-values rather than theoretical and real infiltration rates rather than assumed).
View Image
You calculate the net area of each element of the thermal envelope (for walls, don't forget to deduct for windows and doors), divide area of each by its R-value to get the heat loss coefficient (HLC). Calculate HLC for infiltration losses (air has a specific heat of 0.0182 btu/cf) by multiplying the specific heat of air by the total house volume times the percentage hourly air change rate. Then add up all HLC to get total HLC, which is BTUs per hour per degree delta-T.
Since we must design heat a heat source for the design minimum temperature (DMT), calculate maximum hourly heat loss by multiplying total HLC times maximum delta-T (Tin - DMT). Tin is assumed to be 65°, unless you plan to set the thermostat otherwise.
If you want to calculate annual heating season heat load, multiply total HLC times 24 hours times your local degree-days (HLC x 24 x DD).
This formula, however, is for a vacant house. If there are to be people living in the house, then you must account for human and utility heat gains (approx. 800 btu/hr for each occupant). This changes the balance point temperature (outside temp at which supplemental heat is needed), and effectively reduces the annual DD.
Then there are passive solar gains to take into account. But now we're getting beyond simple and you'll have to take one of my classes to get the whole enchillada.
END Riversong post
All,
Robert's Simple formula showed me where my design weakness was.
In my case I will add more r-value to my walls in the future.
I will also incorporate Energy Recovery Ventilation.
I was duped by local wisdom (Texas) and an Energy Textbook that was written by a Cold Climatist
Just look at the numbers.
Plug your own house into the equation.
Increase the r-value in walls and ceiling on his example to 40 and 60
Now the ventilation piece of the pie becomes more significant.
If the exhaust fans are programed to change the air once every 4 hours there will surely be more than 0.25 ACH due to spot ventilation (showers and cooking)
Since triple glazed windows are still very expensive... then Ventilation is the BEAR in a tight and well insulated house.
My answer to the window problem is to use the best windows that you can afford and then treat them as jewels and place them very carefully depending on your site and climate.
You may not need as many as you thought or you may need more...just treat them wisely.
Also Some climates will not get such a big bang from super insulation.
I want one of those heat and COOL recovery ventilators.
if it were 100 % efficient ( which it isn't ), there would still be a loss
eg : 10 deg outside air vs. 70 deg inside air would result in a net of 40 deg air... but it isn't 100 % efficient... so the net will be lower, like say 30 deg
this 30 deg air then has to be heated to the comfort level of the interior ( 65 - 70 )
You misunderstand the efficiency ratings. 100% efficiency would mean that all exiting heat is recaptured in the incoming stream (except latent heat, unless it is an enthalpic ERV) so that the replacement air is the same temperature as the exhaust air.
Obviously, this is not possible and the best HRVs offer about 75% efficiency, which means they recapture 75% of the sensible heat energy of the exhaust air such that at 10° out and 70° in the inflow would be 55°.
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
that's about the range of numbers i would have expected.....but those links that kiddoc was using were showing higher results
much higher
and, no....i didn't misunderstand.... you just didn't bother reading what i wrote
Mike Hussein Smith Rhode Island : Design / Build / Repair / Restore
Edited 12/29/2008 8:01 pm ET by MikeSmith
and, no....i didn't misunderstand.... you just didn't bother reading what i wrote
Not only did I read every word that you wrote, I also reposted them:
if it were 100 % efficient ( which it isn't ), there would still be a loss<!----><!----><!---->
eg : 10 deg outside air vs. 70 deg inside air would result in a net of 40 deg air...
The definition of 100% efficiency is zero loss.
A 100% efficient HRV exchanging 70° air for 10° air would result in 70° incoming air.
In a static system, 70° air and an equal volume of 10° air would equilibrate at 40°.
But, since this is a dynamic system in which a constant stream of 70° air is passed along a counterflowing stream of 10° air, the maximum heat transfer would result in the two air streams exchanging their temperatures.
The efficiency, then, is the percentage of the delta-T which is "traded". Since the delta-T in your example is 60°, a 75% efficient system would transfer 0.75 x 60° = 45° and raise the incoming air stream to 10° + 45° = 55°.
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
wtf ?
<<<<
if it were 100 % efficient ( which it isn't ), there would still be a loss<!----><!----><!---->
eg : 10 deg outside air vs. 70 deg inside air would result in a net of 40 deg air... >>>>Mike Hussein Smith Rhode Island : Design / Build / Repair / Restore
wtf ?
???????????????
Those were your words.
http://forums.taunton.com/tp-breaktime/messages?msg=114460.44
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
why is it that you have trouble parsing that sentence ?
there was no nuance like the "tucked into sausage "
Mike Hussein Smith Rhode Island : Design / Build / Repair / Restore
why is it that you have trouble parsing that sentence ?
Perhaps because it was illogical and factually incorrect?
Why is it that you can't understand the explanation?
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
Edited 12/29/2008 11:44 pm ET by Riversong
I have a heat recovery ventilator. Actually, the air coming in is often surprisingly warm. Much warmer than I thought it would be before we bought it.
They work quite well. Its not unusual for the air coming in to be say, 55-60 degrees when its 30 outside and 70 inside. That cool air is rapidly diluted in the warmer house air so drafts aren't a problem.On the coldest nights we can turn it off or more often, simply let the heater manage the temperature with a low 1/4 duty cycle of ventilation. It doesn't seem to run much more.Its very nice to have the fresh air without having to open up windows.
Hi Folks,The thing about Passive House that gets overlooked by everyone is how profoundly innovative the design process is to the process every other typical house, custom or otherwise, is designed to in North America.The thing Feist realized with the Passive House process is that if you insulate and seal the house well enough you don't need a technologically complicated and expensive heating system to make up for the buildings heat loss. So, yes your windows will have to be exceptional; triple glazed, fibreglass framed and depending on climate zone with a high SHGC. And you will spend much more on insulation and the labour to ensure that it is detailed right. But you no longer have the expense, complication and maintenance of a high efficiency heating system, whatever the energy source, so you can quite conceivably build a Passive House for marginally more than you would any other energy efficient house, and end up with a house that has a very simple HVAC system that most people can get there head around. (Try explaining how a heat pump works and you'll quickly realize that an HRV is a very simple mechanical device in comparison)As someone who is in the later stages of an addition and renovation of an "energy efficient" house, I have come to realize the elegance of the Passive house approach. I put in a water-to-water geothermal heat pump with radiant flooring as the method of heat distribution. The cost of the the geothermal alone would have gone a long way to bringing the insulation up to Passive House standards.Ideally you'd like to have a site that provides some passive solar heating opportunities, but you can build a Passive House on a north facing site ( i.e. no passive solar benefit). Malcolm Isaac's house in my neck of the woods is an excellent example of a Passive House that does not have passive solar heat gain. If you can build a Passive House on the site he built on, you can build it anywhere.http://www.flickr.com/photos/malcolmi/sets/72157600708203327/As for aesthetic issues, I think folks might be mislead by the e-co lab houses. You have to remember that those houses were built with a really modest budget, so there wasn't room to splurge on siding, etc. The houses were aimed at folks with modest middle incomes. When you think about it Passive Houses are the ideal affordable home, limited maintenance issues, very low monthly energy costs; It's pretty much just the monthly mortgage payment. And the home-owner no longer has to worry about volatile energy prices.
By the way, Malcolm Isaacs will be giving a free presentation on Passive House design at 7:00 on Wednesday January 28 in Chelsea, Quebec at the United Church on Mill Rd. If you are in the area it should be worth attending. I'll post more info about the presentation later.Cheers,Andrew P.S. Oh yeah, the earth tubes idea didn't pan out. This is a an EDU interview with Feist where he talks about Earth tubes amongst many other things...
http://www.passivehouse.us/passiveHouse/Articles_files/EDU%20Jan%2008.PDF
...P.S. Oh yeah, the earth tubes idea didn't pan out. This is a an EDU interview with Feist where he talks about Earth tubes amongst many other things...http://www.passivehouse.us/passiveHouse/Articles_files/EDU%20Jan%2008.PDF
EDU: In North America, many energy-efficient builders
associate earth tubes with condensation and mold.
Have earth tubes in Europe experienced these problems?
Feist: There were problems in northern Europe, especially
in Scandinavia. In Central Europe we haven’t
had any hygienic problems so far. Actually, I’m not
sure why we don’t have these problems in Central
Europe. But I don’t advertise these systems any more,
mainly because they are too expensive. If you have a
good heat-recovery ventilator, you don’t need it. Earth
tubes are just one component of a building; no component
is necessary in every climate.
Problems have occurred in very cold climates — climates
that are cold during the summer as well as the
winter, and humid all year. Even in Central Europe,
it is humid during the summer, and no doubt you get
condensation. But we don’t get mold growth, and I’m
not sure why. We always try to get a better scientific
understanding of such things, but it’s not always possible
to do the research, since research is very expensive.
I am a little bit skeptical about that earth-tube technology,
and now it is clear that it is not necessary to use it.
94969.19 In the beginning there was Breaktime...
Actually, I’m not
sure why we don’t have these problems in Central
Europe.
Rezinator,
Yep .. Wolfgang screwed up
and he moved on just like we all do.
BTW why don't you link your time machine to page 1 of the photo contents page also?
JB
But you no longer have the expense, complication and maintenance of a high efficiency heating system, whatever the energy source, so you can quite conceivably build a Passive House for marginally more than you would any other energy efficient house
The same thing is true of a well-designed American-style superinsulated home. The first two I built required only very small woodstoves (no central heat), which was also the homeowner's preference, as they each had woodlots, and the homes needed only 4/5 of a cord of wood per year.
When you think about it Passive Houses are the ideal affordable home, limited maintenance issues, very low monthly energy costs; It's pretty much just the monthly mortgage payment
Similarly with superinsulation, but without going to the extremes of PassivHaus, the monthly housing costs are less than an energy-code home from day one: marginally higher mortgage more than offset by significantly smaller heating requirements (and no cooling requirements in a northern clime).
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
Super insulated, passive solar, thermal mass inside to help maintain temps... all these I'm onboard with.
What I want to know is how can you get rid of the humidity without running an AC or heat pump unit?
I suppose you could create a heat sink wall that had ground tubing running fluid through it. The humidity would condense on the wall and run down it into a drain (like a sweating glass of ice water), but I doubt that this would provide an effective removal of humidity (and you're going to have to keep a pump running).
jt8
A year from now you may wish you had started today. -- Karen Lamb
Depends on location more than anything..
We're able to simply open our windowsduring the summer.. the design and location makes my house pleasant on even 90 degree days only days well in excess of 90 degrees require A/C Last year that was 2 days!
We can get over 100F with a 90+ humidity. "blech" weather.
jt8
A year from now you may wish you had started today. -- Karen Lamb
Minnesota is rare to get that high a temp plus my microclimate tends to be softer than that because of the proximity of the lake..
Ironic I'm cooler in the summer and a tiny bit warmer in the winter due to Mother nature being nice about where she put her lake
What I want to know is how can you get rid of the humidity without running an AC or heat pump unit?
Mechanical ventilation.
Excess air exchange in the winter is the cause of low interior relative humidity in a leaky house. In a tight house, measured air exchange will eliminate excess humidity.
A typical family of four will contribute about 3 gallons of moisture per day to the inside environment.
In a 2000 sf house at 68°/40% RH inside on a 32°/80% RH day, the recommended 0.35 ACH would evacuate 0.13 gal/hr or 3.12 gal/day.
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
No, I mean get rid of the humidity during the long, hot, humid summer.
jt8
A year from now you may wish you had started today. -- Karen Lamb
I mean get rid of the humidity during the long, hot, humid summer.
Well, since you list your location only as "NEast of Boss Hog, SWest of Stan", I couldn't really tell what kind of climate you're in.
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
Central IL.
Jon Blakemore RappahannockINC.com Fredericksburg, VA
I mean get rid of the humidity during the long, hot, humid summer.
I live where there are two predominant seasons: winter and mud season (there's also tourist season, leaf-peeper season and ski season, but those are for flatlanders).
When I worked in northern Minnesota, we also had just two seasons: winter and 4th of July.
But one of the advantages of a super-insulated house is that it also remains very cool in the summer and doesn't require as much open-window ventilation.
If the house is built with hygroscopic materials, then it can buffer the relative humidity (just like thermal mass reduces temperature swings). If not, then significant dehumidification would likely be required through air-conditioning and maintenance of positive pressure.
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
You forgot Monrealers driving down to Burlington to shop when their dollar is high season - which moves around a bit like easter.
"But one of the advantages of a super-insulated house is that it also remains very cool in the summer and doesn't require as much open-window ventilation."But in the South it would not since at night its 88 degrees outside and high humidity- that humidity would be worse inside the house- right? still need a dehumidifier like an Air conditioner
But in the South it would not since at night its 88 degrees outside and high humidity- that humidity would be worse inside the house- right? still need a dehumidifier like an Air conditioner
Maybe not much of one with proper shading, ventilation, and fans.
Check out the Florida Cracker House:
http://www.phys.ufl.edu/~liz/home.html
click on the HVAC link at the bottom
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
They say
'So, how does our Friedrich AC work? We really haven't had it long enough to know yet. It is sized for a maximum room size of about 700 square feet. It is in a room of 625 square feet floor area, but with high ceilings. Also, we usually have it open to the whole house when it runs, which is 1400 square feet with high ceilings. On a typical day, after about an hour of running, the humidity will have dropped about 4 points and the temperature about 1 degree (F) in the side of the house farthest from the AC. Unfortunately, most days when you really need it, it is fairly cloudy and hazy out, so we can't afford the power to use it. More data will be provided as it becomes available. This picture shows the Friedrich air conditioner mounted in a solid door, which replaced one of the glass doors looking from the bedroom out onto the west porch. "I ask : when its 105 degrees outside and it just rained they are sweating? and at 8 PM bedtime when there is no breeze and its 100% RH and 90 degrees!!!!!!!
Edited 1/2/2009 7:22 pm ET by edwardh1
But to build the passive house (northern-style) in, say, Dade County FLA, would be doing the "right thing wrong".
Flathead,
I would not suggest that you build passive house northern style in a hot humid climate. The concepts will work in any climate.
Airtight, well ventilated, thermal bridge free, climate appropriate r-values,energy recovery.
Edit to add Not Vapor tight
Edited 12/29/2008 10:24 am by homedesign
I enjoy the cheezy newspaper articles written for Nevada probably,but printed in our Southern Sunday newspaper about how you can be cool by opening the top of the window and the bottom and allowing the air to circulate and here its 90 degrees and 90 % humidity at 8 PM.
We can design passive without solar.
Yes, but is it wise? We, like all living things - in fact, like the Earth herself - are solar-powered creatures. The sun literaly courses through our veins.
To build in such a way as to lock out the sun, when it offers us so many benefits - free heat, free convective cooling, light, better moods, health - is to defy our very biology and the gifts of the planet which birthed us.
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
We can design passive without solar.
Yes, but is it wise? We, like all living things - in fact, like the Earth herself - are solar-powered creatures. The sun literaly courses through our veins.
It may well be wise, in that if we allow for narrower lots and dense infill housing, we can solve a lot of issues. The American house featured in the article is in central Berkeley, where the lots average 35 feet wide. Not a lot of solar gain in many cases, but still more ecologically sound than a perfectly effecient house in Livermore where the owner drives two hours each way to his or her job in the city.
k
...but still more ecologically sound than a perfectly effecient house in Livermore where the owner drives two hours each way to his or her job in the city.
Are you suggesting that American suburbs are not "green"? ;-)
Hell, that's all I see in the suburbs is green - acres of grass and acres of $.
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
And I'm not entirely a true believer in density at all costs either- around here it is mostly used as an excuse to give big connected developers variances on height, setbacks and such for ridiculously large condo blocks. Google The Gaia Building sometime...
Passive solar is not an option in many dense residential areas. But the dense residential neighborhoods of the inner east bay are quite livable and green (in all senses), lots of bike lanes etc. even if passive solar isn't real effective.
Just noting the difference btw passive solar and passive, and leaving the question of how "worth it" it is aside for now.
And frankly, considering the embodied energy in the German triple paned windows, I don't know that the math would work for those in Berkeley, energywise. (I'm fairly certain it wouldn't work moneywise...)
k
The thing is you can compare a Prius to other available cars quite easily. There are only a few manufactures and they are required to show EPA mileage figures. Houses are all different and most builders have no incentive to produce an efficient house because it is impossible for a consumer to really assess the differences from one house to another.
Here is Maine, a pretty cold climate, most builders' contribution to energy efficiency is to use 2x6 studs instead of 2x4 and do the same lousy job of stuffing fiberglass between them. Most plumbers are installing the same boiler they installed years ago, etc. We finally get an energy code next year, but it won't apply to towns (like mine) with fewer than 2000 people. We don't have any building code.
The Germans have decided that it makes sense to use a combination of incentives, code requirements and taxes to create more efficient use of energy. Here in the US, no politician would dare suggest such steps.
Houses are all different and most builders have no incentive to produce an efficient house because it is impossible for a consumer to really assess the differences from one house to another.
Only until home buyers begin to demand an efficiency score, like we're used to now for cars and appliances, which is the function of the HERS (home energy rating system) used by Energy Star and RESNET and many state efficiency programs.
Here in the US, no politician would dare suggest such steps.
They don't have to. The NAHB is really pushing efficiency and green standards because they recognize that's where the market is going. Any smart builder would jump on this bandwagon.
The National Association of Home Builders (NAHB) National Green Building Program has been developed by the NAHB Research Center. It is a point-based program that promotes green building practices in lot design, preparation and development; resource efficiency; energy efficiency; water efficiency; indoor environmental quality; operation, maintenance and homeowner education; and global impact.Builders Energy Rater is a NAHB approved Green Verifier. In addition to providing ENERGY STAR¯ certification on your project, we can also provide the 3rd party inspections and testing required for this program.
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
a couple of notes that may be helpful:many components in germany are developed specifically for PH, and are tested and certified by the PH institute. this includes:- windows at R7 overall, SHGC above 0.5
- heat recovery ventilators above 80% effectiveness (many of them above 90%!). they use a true counterflow heat exchanger in most, which i have not been able to find at residential scale in the US. the only machine i know of in the US that can do this, and meet the PH fan power requirement, is the UltimateAir Recoupaerator.
despite these differences, it has been done in the US using 100% north american products (yay!)A lot of the research for the PH method was done in the US and Canada. so no it's nothing new, it's just extremely rigorous and very precisely defined (see below).another difference is the PH Planning Package - it's an excel sheet that allows you to be VERY exact about the heating loads, and plan a miniscule heating system around it (with the power of a hair dryer). the idea is that, assuming a distributed fresh air ventilation system, get the loads low enough that all you have to do the meet the peak heating load is put a duct heater in the fresh air supply. however, that's not the only method used in germany, and some in the US are using single point-sources so that e.g. wood or a ductless minisplit can be easily done.
You think so? I'd like to know if their govenment is helping out.
If the govenment backs $ things it gets a lot easier to do.
•100-foot long earth-tube air intake for pre-heating and -cooling.
I'm in central IL, and I'd be very careful about using earth tubes for air. Sounds like a recipe for mold in this climate. I need to go read the links about the house.
jt8
A year from now you may wish you had started today. -- Karen Lamb
Yeah, I think the air tubes concept has been debunked. I read a
rather negative cost performance evaluation on some research
website -- perhaps Oak Ridge. To say nothing about the risk of
mold.
I looked into Passiv Haus for my current Japanese project.
The upcharge on the superwindows alone would have added
10% to my costs.I think the reason why they can claim only a 5 to 7% upcharge in Germany is that the standard is already so high. Building code already requires you to have an HRV, for instance, and the windows are already very good.Only 15,000 Passive Haus houses over 17 years is a drop in the bucket. The big omission by the clueless writer of this article is that Germany just fulfilled their Kyoto Protocol commitment, the only country to do so. I suspect that their energy standard for housing, which is the highest in the world, made the largest contribution to this achievement.Or, in short, the cheapest and easiest thing the world can do to combat climate change and dwindling energy supplies is just to add more fiberglass insulation to ceilings and walls.
I think the reason why they can claim only a 5 to 7% upcharge in Germany is that the standard is already so high. Building code already requires you to have an HRV, for instance, and the windows are already very good.
IIRC, Germany also has one of the most agressive programs to promote active alternative energy systems like photo voltaic and turbines. I believe it was something about a guarantee to purchase the resulting green energy at a fixed (somewhat high) rate for X number of years. This makes it so attractive for the average person to add alternative energy (even on a very small scale) that they have had an explosion in related sales.
jt8
A year from now you may wish you had started today. -- Karen Lamb
Edited 12/28/2008 2:31 am by JohnT8
Germany also has one of the most agressive programs to promote active alternative energy systems
Germany has also been way ahead of the world on indoor health with their Bau Biologie movement.
And lower Saxony, I believe, is the first jurisdiction in the world to mandate "cradle-to-cradle" manufacturing, by which every company must take back their products at the end of their use for dismantling, and recycling or composting.
This grew out of the Milennial World's Fair in Hannover, which was the first dedicated to sustainability, and for which US architect William McDonough created the Hannover Priniciples and developed his Cradle-to-Cradle philosophy.
THE HANNOVER PRINCIPLES
1. Insist on rights of humanity and nature to co-exist in a healthy, supportive, diverse and sustainable condition.
2. Recognize interdependence. The elements of human design interact with and depend upon the natural world, with broad and diverse implications at every scale. Expand design considerations to recognizing even distant effects.
3. Respect relationships between spirit and matter. Consider all aspects of human settlement including community, dwelling, industry and trade in terms of existing and evolving connections between spiritual and material consciousness.
4. Accept responsibility for the consequences of design decisions upon human well-being, the viability of natural systems and their right to co-exist.
5. Create safe objects of long-term value. Do not burden future generations with requirements for maintenance or vigilant administration of potential danger due to the careless creation of products, processes or standards.
6. Eliminate the concept of waste. Evaluate and optimize the full life-cycle of products and processes, to approach the state of natural systems, in which there is no waste.
7. Rely on natural energy flows. Human designs should, like the living world, derive their creative forces from perpetual solar income. Incorporate this energy efficiently and safely for responsible use.
8. Understand the limitations of design. No human creation lasts forever and design does not solve a problems. Those who create and plan should practice humility in the face of nature. Treat nature as a model and mentor, not as an inconvenience to be evaded or controlled.
9. Seek constant improvement by the sharing of knowledge. Encourage direct and open communication between colleagues, patrons, manufacturers and users to link long term sustainable considerations with ethical responsibility, and re-establish the integral relationship between natural processes and human activity.
http://en.wikipedia.org/wiki/Hannover_Principles
http://www.mcdonough.com/cradle_to_cradle.htm
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
wonder how buying stuff made in China fits into the Hannover principle
No mention of an "earth tube" in the NYT article about German houses.5-7% upcharge for passive was compared to similar construction in Germany. Partly made possible because there are local manufacturers for the complicated door/window systems, but probably also because conventional building standards are higher/more expensive. Also, many builds seem to be town houses, rather than single family dwellings. NYT times writer was blunt that costs would be way over 5-7% higher for comparable construction in this county -- primarily because these kind of door/window systems are not yet produced in sufficient quantity in US.They use a sophisticated air cleaner along with the heat exchanger -- which eliminates potential mold problems. They are now doing research to figure out how it can be configured for warm climates. This style of design, according to the German architects, works best for small, compact houses -- 500 SF per person. Not many Americans (who can afford to build a house) are looking for a 1500 SF home -- even with the trend toward "smaller is better."Homedesign gave link to the German website. This institute now has an affiliate in US:http://www.passivehouse.us/passiveHouse/PHIUSHome.html********************************************************
"It is what we learn after we think we know it all, that counts."
John Wooden 1910-
Or, in short, the cheapest and easiest thing the world can do to combat climate change and dwindling energy supplies is just to add more fiberglass insulation to ceilings and walls.
Nooooooooooooooooooooo!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Anything but fiberglass. It's the closest thing to worthless an insulation can be. It's popularity is due exclusively to low price and millions of dollars worth of advertising.
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
>Anything but fiberglass. It's the closest thing to worthless an insulation can be. It's popularity is due exclusively to low price and millions of dollars worth of advertising.
Add convenience, in some cases. I just insulated the roof of my 2-story garage with fiberglass batts. I was really interested in blowing cellulose, but I have a lot of stuff stored there already. Blowing in cellulose is something you need to do pretty much all at once, which would have meant finding a place for all the junk while I was doing it.
Using fiberglass, I can move stuff around as I go.
It's a garage which will be heated sporadically with a wood, and I'm usually happy to have it at about 50 degrees when I'm working in there, so I'm not as worried about optimizing the envelope as I would be in a continuously heated house.
Don
I could argue against the NYT article as regards the window and systems points. The claim is made that the US windows and air systems technologies are not up to par enough to use in a passive solar house of the design cited.
A neighbor of ours bought a south-facing site across town from where we are, and is having a passive solar house, a whopper at close to 5200 sf for two retired people, built per the design by Adirondack Alternative Energy.
With most all its glass (windows by Andersen) facing south, and all trees whacked for 130 feet or more on the S, E, and W sides, the house is wrapped on all six sides with a continuous layer of Thermax board, two layers each 2 inches, joints staggered, all joints taped. There is no other insulation in the 2x6 wallframe cavities.
The house is a story and a half on a full walkout basement, and the foundation is unconventional. A full 12-inch bed of compacted gravel is laid, drained at its perimeter, then go the two layers of thermax board laid on a cushion of #30 felt, atop which is built a 12" slab of concrete. The crete goes down first as a 2" ratslab, then an array of ducting is laid, then fully encased with the last 10 inches of thickness.
That big slab, insulated from below, housing its network of ducts, is the heat storage battery for the house.
View Image
"A stripe is just as real as a dadgummed flower."
Gene Davis 1920-1985
Interesting except for the 500 ft2 per person part. ok for 4 (2000 ft2) but tight for 2 - 1000
Edited 2/26/2009 8:25 am ET by edwardh1