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Ducting for heat - registers high or low?

3424 Views 11 Replies 3 Participants Last post by  Jim W
I'm beginning to work out the ductwork for a new furnace installation (added 1000 feet still under construction) with no existing ducting.
The house is a long narrow 2 story with a 500 sq ft lower room downstairs. The furnace will be a gas fired up-draft located centrally on the 1st floor. The ducts will run through the attic/trusses but I also need to get some heat downstairs as well.
The downstairs is built from ICF walls and the only way I can have registers at the floor would be to make a false wall. If I put the registers in the cieling it would be much easier but I think that it won't be very efficient (due to heat rise).

Any ideas? Also, has anyone used those online duct engineering services? Apparently you send them a sketch of your floorplan showing rooms and joist direction/spacing and they do a take-off for you.

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Select supply registers with a downward throw.
And put your returns low.
Beenthere, thanks for responding so quickly. You mention that I should put the returns low. This defeats the concept of not running duct down the ICF walls. If I could put the returns low, I'd simply put the registers low and move on. Am I not understanding something?

Jim W
I get it - that was just me being too serious :yes:

I'll probably have only one return - in the short hallway right infront of the furnace. The location is pretty central to the main floor floorplan and is probably all I need.
The downstairs will be the toughest to heat because of all the mass in the ICF walls and I fear most of it is just going to go right up the open stairwell.
Maybe putting the "downflow" register as far from the stairs is the best I can hope for.

Jim W
I have read that if the interior doors are about 1 1/2 to 2" from the floor that this is enough to transfer return air for most bedrooms - which are the only rooms I have with doors other than bathrooms.

Is this a poor way of doing it?
Thanks Beenthere,
Everyone here has been very helpful

What is your take on a "duct design Service"
I have a autocad floorplan and can send a PDF file to them
for around 400 bucks they do a take-off and give me a materials list and drawing. Sounds kinda spendy

Jim W
1 - 6 of 12 Posts
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