DIY circulation solution – must be quiet, energy effecient, simple, low cost
This is a continuation of another post but the focus is a bit different so…
I am building a 25×25, two story that will be heated mostly with a centrally located wood stove. The layout is wide open (no partition wall on first floor) so good radiant distribution but with wood heat you get vertical stratification.
I would like to design something fairly simple meaning not a complex system of ducting throught the house.
Seems like it should be not to difficult to build a couple of ducts that simply pull air off the ceiling and vents it out at floor level.
? >> One question is how much air do I need to circulate per hour as a percentage of total cubic footage to be effective in eliminating stratification? Is one air change per hour enough? more? less?
Then I’ll know how to spec my fans.
? >> What is a good solution for a fan to move the air? The considerations are: low power and VERY quiet. (no ceiling fans, they just don’t do the job)
I don’t consider a fan than pulls 100 watts to be low power. I don’t care if it has an Energy Star sticker or not. The house is off-grid so power will be a combo of solar, generator and storage batteries. Especialy when power is coming off the batteries every watt counts.
And I don’t want to hear this thing whinning and rattling away as it will run most of the time.
There are Broan exhaust fans that are rated at 50-80 CFM and operate at .3 sones which is about as quiet as it gets.
Seem like I could duct this fan out to the floor level. (no I’m not talking about using this in a bath. This is to circulate air only and of course I’ll need exhaust in the kitchen and bath areas)
I’ve looked at in-line fans but they never seem to give enough info on power usage or noise levels. If this seems the way to go could you recommend a few options that meet the criteria?
Any reason I couldn’t adapt the exhaust fan to my purposes?
?>> If am outputting air at floor level in a high traffic area will this create an uncomfortable draft? It will be warm air but still a draft.
Looking for a low cost, low energy, quiet DIY solution.
Thanks for any input!
Replies
Several times this has been discussed here: Get someone to sew you some cloth tubes -- maybe 12-18" in diameter (remember pies are square, but are two pie diamaters around), and long enough to reach from near the peak to down near the floor. Attach the tubes to rings near the peak and position suitably sized table-style fans inside the rings.
fenster
Like I mentioned in the other thread, we have a passive air movement system from open greatroom corner on the house, up and over to remote BR's. From there, floor register to downstairs (in the opposite corner from greatroom).
A panasonic remote ventilation box away from the inlet of an active system will move as rated cfm's and is VERY quiet. You only hear the air moving past the grill.
For your freshair changes you could use an HRV system I suppose, separately.
One or two systems?
Thanks. Do you know the model line of remote box that you used?
One other question. THe house will be two story. Second floor will be T&G over beams with floor registers to control heat flow to secnd floor.
If I install an active air criculator such as you mention (and what I am leaning towards) then should I pul air from top of the second floor and exhaust to floor level on first floor? Or have one sytem for each floor?
Oh, how much air do I need to move? How many air changes per hour to be effective?
Thanks
Happy Holidays!
should I pul air from top of the second floor and exhaust to floor level on first floor?
Yes.
use a couple of surplus muffin fans form old computers.
100 cfm should be good for you
Of course, you need a surplus computer power supply to run them, and the fan on that screams like a banshee.
fenster
I don't have the model number for you, but it was a 250 CFM fan that required 6" pipe.
My passive system pulls from the open 2 story greatroom, and exits at the other end of the house through floor registers.
Active? I still might pull the air near the floor of the upper level so it is more comfortable in the winter, no need for the heat to be up high. Now, I'm no HVAC person. I might bring this up at a forum called "heatinghelp.com" I believe..............The know path, volume, balance details that I would just be experimenting with.
One bit of experience I do have is 20 yrs of this passive air movement with in slab radiant heat.......................soapstone masonry heater for fall/spring and throughout the winter as a sole heat system.
If you do go over to heatinghelp, please come back with some of the ideas so we all can become educated on this subject.
thanks.
For cfm ... hmm maybe consider about 1 cfm/sqft of floor area ... about the same as a heating/cooling system. You might go less, but not sure. Maybe shoot for around 2-4 ACH.
You can buy some super quiet Panasonic in line fans ... I used them for exhaust fans for bathrooms. VERY quiet ... and very inexpensive. I bought a couple of 250 cfm units for like $100 each. I often forget to turn them off 'cause they are so quiet.
I'd run your ducts between floors .. ceiling of 2nd to floor of first ... allow for circulation in between ... do you have an open stairwell? That might work.
between floors
Actualy there won't be a between-floors as I will have T&G flooring over beams. So heat should transfer pretty easily to the second floor. All the more reason to circulate. So that makes ducting more of a challeng. But I could run it above the 2nd floor ceiling and down a side wall.
I will have an open stairs however and floor registers. so if I suck the air off the 2nd floor to the first I should get lots of air circulating.
On the first floor the wood stove will be on one end of the space so was thinking to exhaust the air from the ceiling of floor 2 to the floor at the opposite side of the space from the stove. Should help even out the floor temperature on the first floor.
With T&G on the second floor, keeping that flooring warm seems like it will take care of itself.
The open stair comes down right by the front door. There will be an arctiv entry but still it will likely be a cold spot. So will hot air rise up the stairs or cold air fall down and pool by the cooler door?
Hmmm.
greg
Hang the cloth tubes down the open stairwell.
The entry will be the coolest place ... because of comings and goings. Conceptually, if you sucked the air from the vicinity of the entry floor and dumped it near the ceiling at the stove you'd promote good circulation.
T&G flooring shouldn't be a problem to install floor registers or run duct through I'd think.
Seems if you have warm floors on the second floor, the issue of stratification may be diminished ... kind of like a radiant floor system where you can turn down the space temp a couple of degrees because of the warm floor on your feet.
Maybe install a floor register near the stove ... warm/hot air flows to the 2nd level and then down the stair. Diminishes the need for fan forced air maybe or at least minimize some cfm requirement.
need to evaluate where you need the heat the most and plan around that. I like bedrooms on the cool side and living rooms on the warmer side.
625 sq. ft on each floor is quite small, so my guess is that a wood burner on the main floor will heat the place very successfully without going to the bother of circulating the air. Our house is 1200 sq. ft. on one level, and we heat it very cheaply and comfortably with a gas-fired Vermont Castings stove that sits in one corner. The back bedrooms are cooler than the rest of the house, and that's the way we like it.
But, just in case, why not build a chase on an outside wall that runs vertically from the upper ceiling level to the lower floor level. Try using the stove without any fan for a season, and if you find you need a fan, you will have the chase ready.