[jake09mid]

I’ve moved into a new house and was looking over the HVAC unit in my basement that supplies the finished part of the basement and main floor. The unit is in the unfinished part of the basement. I noticed there’s a 4 inch 45 degree angled duct installed on the supply plenum that is just dumping warm air into the unfinished part of the basement. Is that some kind of standard or is there a reason for this vent? Seems inefficient to waste heated or cooled air...can I cap it?

 

[surferdude2]

I'd consider it beneficial in the winter and leave it alone... maybe cap in in the summer unless the basement got real smelly. I have both suppply and returns in my basement. Stays nice with no clammy basement odor.

 

[lenaitch]

It might be unfinished but it's still part of the conditioned space. I assume it is an easy way for them to do it; our daughter's house has something similar.

 

[Bud9051]

Before making any change I would review the combustion air needs, assuming a gas or oil furnace. May not be an issue or may be necessary.

Bud