I am in the process of building my first home. When I say builiding I mean I am the GC on my own home and hiring the contractors and subs. My question at this point is…What will be the most efficient system for a home in Vermont that is built into a hill. I have a Prow style with a walkout basement, and I need to keep a budget in mind. The quote I first got was a forced hot air system and radiant in the slab, and half of the first floor. The forced hot air was to suplement and extreme Vermont temperatures and help with the upstairs. The sq footage is about 2400, not including the 1200 sq foot basement. I had a contractor suggest just going with the Radiant and combine it with baseboard. Another contractor suggested a Boiler with an air handler. I will need to to keep a quality window in mind and was pricing out Simonton, Pella, Anderson, and Marvin. I thought that vinyl windows would still offer good quality but a lot of people are suggesting wood.
Any thoughts?
Replies
Welcome to Breaktime.
It's great that you're thinking of using a high-quality window. What are your other construction details? Extra effort put into insulation and air sealing can make a big difference in the size of your heating equipment, and will reduce or eliminate drafts.
Radiant floor heat is great (NRT Rob is the Breaktime expert) but at the design/build company where I work we have found that an air system has many benefits as well.
thanks for the kind words mike.it's true that air systems have flexibility radiant does not, but they are never more efficient. They can be cheaper, but are not always.Set into a hill, in vermont, I would suspect cooling to be unnecessary. If so, an ERV ventilation system, slab radiant, and panel radiators on the 2nd floor can be extremely cost effective and comfortable year round.If cooling is necessary, the air system must be upsized, and then the economics of doing heating with air are strong... but there is a sacrifice of distribution efficiency and generally of comfort with that choice, in most cases. but not all. Passivhaus brings it all down to parity ;)-------------------------------------
-=Northeast Radiant Technology=-
Radiant Design, Consultation, Parts Supply
http://www.NRTradiant.com
Never more efficient? You should know better Rob. I agree with the rest..
Never and always are words you should always never use. :)
Never say never ...
You're right, of course. I should have said *Given equally well designed and installed systems, forced air is never more efficient". Fan power guarantees it if nothing else.but if the radiant is not insulated properly, or any poor system vs any good system can change those comparisons, for sure.-------------------------------------
-=Northeast Radiant Technology=-
Radiant Design, Consultation, Parts Supply
http://www.NRTradiant.com
Seems like radiant is more forgiving of a poor envelope, in that it's less inclined to produce drafts?
It's more comfortable, yes, and you don't have to worry about duct leakage and loss. But that said, poor envelopes can easily present challenges radiant floor alone cannot meet where forced air can almost always be sized to dump enough heat into a room to keep it warm. Radiant has limits. Air, not so much.but the worse the heat load (up to the max) the more noticeable radiant comfort is too. It's also easier to zone for highly variable envelopes.I wouldn't say necessarily radiant is better for any particular envelope type though except tall ones: with its limited stratification it can be a significantly more efficient choice for cathedral or tall areas. But It all depends on how good of a system it is, vs the one that could have been. If both systems could have been good, then radiant will be better, and the question then is "by how much". the answer THERE lies in comfort first, and somewhat in efficiency as well.. even in passive houses, radiant is better than the air handler option... but perhaps not so much better that it matters or is worth the cost. *it depends* :D-------------------------------------
-=Northeast Radiant Technology=-
Radiant Design, Consultation, Parts Supply
http://www.NRTradiant.com
If you haven't started building and you are willing to invest for the future than I'd suggest you look at the Passive House approach. A good HVAC system for a typical house will cost a lot of money, take the money out of the HVAC and put it in the building envelope instead.
I put in radiant in my house, the heat is from a ground source heat pump, with an HRV for ventilation and found it quite a challenge to design and implement.
As you have to deal with the building envelope anyway, instead of doing a half-#### job as is typically done, instead focus on building a really good envelope. After that the HVAC is that much smaller, and that much less of a hassle to design, install and maintain. And you are no longer at the mercy of volatile energy prices.
Hi NCYVT,
Heating, windows, insulation, etc.
The fella's here have already pointed you in the right direction and I must agree from living experience.....the envelope is your first point of focus.....sufficient insulation, thermal break using something like insulating panels, windows with "Low-E" glazing are a must, weather sealing.....caulk and canned foam are cheap insurance against energy lost, materials protection and insect infiltration......this is one thing you can do yourself after hours when you go by to check up on your job each day.
Pick up and sweep up everyday. It'll go a long ways in keeping dust at bay after everything is buttoned up. With good subs, they'll recognize how much you care about your house and will follow suit.
I'm a strong believer in metal roofing. It's a one time roof that'll pay for itself over time in comfort and energy savings, not to mention the durability and never having to pay for a tear off and disposal then replacement. Extra up front makes the difference.
Good job planning in advance, keep checking back and ask all the questions you need.
In your area the very least I'd do for the walls are 2x6 24" OC with R19 fiberglass infill and 2" polyiso insulating panels as a thermal break. R38 + 2" polyiso panels for the roof.....all ductwork should be inside the thermal envelope. Insulate the slab too.
If the budget allows, I'd consider SIP's for the whole thing.
I put in 10' ceilings in my basement which was a inexpensive way to make certain I had room to run all my ductwork, plumbing etc. and still have room for a 8'+ ceiling. And I put 2" pvc chases between floors for possible wiring runs in the future.
Pedro the Mule - Quite efficient myself but still learning
OK, a lot of ... reduce the load stuff creaping in here in the form of 'better envelope', sealing, etc. So ... I'll jump in w/ my 2 cents.
First ... TOTALLY agree w/ maximizing the quality of the thermal envelope. What I don't hear much along thes lines is reducing the size of the envelope (i.e. volume, surface area). How? I know everyone tends to dislike discussing this ... but it's by decreasing your floor area.
Keep in mind in reading my comments ... I know NOTHING about your family, lifestyle, and your 'needs'. With that in mind, the biggest mistake I see people make is overdesigning their floor area. Thinking they need much more than they really do. They want much more, but they often may only need a little more. This is particularly true if your current conditions make you feel squeezed for space.
So, I would encourage you to (if not already done so) simply reassess your floor space needs. 2400 sqft sounds like a lot ... you must have a large family (5 or more). It can be hard to trim a design. Mark my words, in the 'future', you will see a profound shift to 'smaller is better'. High quality, smaller houses. I'm not saying you give up your needs, but assess the difference between wants and needs. True architectural design addresses this kind of thing. Can you believe the average house size in Boulder CO is like up around 5,500 sqft!!! OMG is that over the top or what. They will regret it, though.
If you are using a stock plan, consider taking some copies and see what kind of trimming you might tolerate. Use no judgements on how each room change will affect others, just go through it. It may talk to you and give you some ideas about trimming the fat. You may discover your true needs and begin to reduce the shear size of your load.
Hey, maybe you've done this already. That's fine. Just food for thought. Maybe this applies to someone else.
Clewless1: Great advice. I also acknowledge that the size/shape of a residence must meet the demands of the family that will occupy the structure. However, I changed just a few things - 10' ceilings, open floor design, large flowing kitchen and larger MBR BUT reduced the sq. ft. by @22%. Looks bigger than the house I left with a greater amount of living space but not as aerodynamically designed. You can do many 'cheap' things to make any space appear larger. The builder talked me into a multiple faced moulding - said the shadow lines would make the room look larger - and it does.All that said - I agree with your statement completely.Mike