return air duct in basement

[mattmeitzner]

I am finishing my basement. There was previously one duct to supply the entire unfinished basement with air, which left it a little cool in the winter. Now I'm creating a mechanical room of only about 150 sqft, a bathroom of 50 sqft, and a main room of about 700 sqft. I have added two additional supply lines to heat the basement to a comfortable temperature, and plan to install the requisite two combustion air grates to "connect" the mechanical and main room. Do I need to add a return air duct as well? Is it advisable or not for any particular reason?

[ransley]

I did the same and put in a closeable return, I only open it when im working in the basement as it seems to heat faster. If the basement needs AC it should cool it better as well and circulate air better

[John Grabowski]

If you are planning to install a bath fan that will exhaust to the outside, you should install a small duct to provide make up air from outside into the furnace room. There have been issues with basement bath fans pulling flue gases down the chimney and into the basement.

[J.A. Michel]

I would put returns in the basement. The air circulation will help maintain an more even temp, and will help dehudimidify the basement when you're running the AC in the summer.

[udarrell]

Any fuel burning heating systems in a basement must be sealed from a Return Air!

udarrell

[Mark]

no do not add a return in the basement..

you do not want to lower the air pressure in the basement because this is bad for combustion air supply and can pull in radon.

Mark