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cold air return reconfiguration question.

1K views 6 replies 3 participants last post by  hummer4x4guy 
#1 ·
Back to work on the furnace duct work today.

Q: I have 4 cold air returns in my trilevel house one on main floor one 2 on upper floor and one on belowground floor. The C.A.R on the main floor travls through bout 7-8' of duct work. Is there any reason I cant simply have that one C.A.R draw air from the basement? Isn't it more efficent to heat the coolest air possible? Would also help to get the air in the basment moving since it will also be drawing air into the basement (basement is technically a 4th level.)

I took a peek inside that duct work and it needs to be vac'ed out badly so I am going to disconnect it for now and get the shopvac out and do it to it.
Also with my future plans for the main floor where the C.A.R in question sits it would need to be moved or rerouted somehow down the road. I would think that my idea would be simple and not an idea with any bad repercusion.
Thanks for any ideas all
Joel
 
#3 ·
Yes there is a door going down to the basement but I generally keep it open and it does have a good 1" floor gap if it is closed. I wasn't thinking of closing off all the others since I believe in pulling air in from all points of the house. I was reading on another site of a woman wanting to do the same idea and people were mentioning that the idea could cause a backdraft on my open vented water heater. The particular C.A.R has had a giant speration in it enough that I can see inside with a flashlight and see all the dust stuck to the inside....
 
#4 ·
if the heater is near the furnace it might but with the others it relieves it totally pulling.if your filter slips into the duct for the furnace on that return duct to it that area can only see so much air coming back that was why i suggested cheating the others so all four are pulling...is the basement seeing heating from the furnace... if not, i won't return it furnaces can only have a certain temperature rise and bringing anything but tempered heated air from a conditioned space will only make the heating cycle longer..
 
#5 ·
If the heater is near the furnace it might?...what? cause a backdraft? As of now I removed the end of the run on the CAR and holy God I sucked out about 3 lbs of dust stuck on the inside. sick!

Yes the CAR in question does have the filter on that run...but all the CAR's have to go through the filter also.
Basement is not heat. It is just a regular basement not for living space. Tho the basement only gets down to 60ish, not to mention the CAR in question can still draw in air from the main level of the house and now also from the basement so it sorta has a mixture of cooler basement air and heated living room air. I have a CO2 detector right in the area of the furnace and WH to keep track if a large enough backdraft ever happens tho I hightly doubt it would.
Thanks for the input biggles.
 
#6 ·
If you do away with the CAR on the floors than you will short the furnace on the volume of cold air it was designed to run on. Less volume back means less flow out and an over heated furnace.

one RA will not be capable of pulling all the home air back to the furnace.

This is an old idea that was made popular by very early handyman and diy radio talk shows. When the furnace started losing heat exchangers the law suits started rolling in and killed of a lot of these under informed diy shows.
Now, locally any diy show I have listened too has nixed this idea of closing RAs for the reasons I stated.

Multi level splits are hardest to heat/cool evenly..that is why they are such good candidates for running the blower 24/7 to even out the temps. ECM motors are the perfect solution for these homes.
 
#7 ·
hvac,
I will keep all the CAR open and as they are. The furnace does have the ECM motor and is 98.5%. Luckily the house stays pretty well evenly heated its not a huge house. 3 bedroom and its only me and a roommate.
I have a feeling things will go just find with the small change I made.
 
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