I have an unfinished basement. It has cement floors with stone walls. The furnace is located in the basement. There is a supply vent blowing conditioned air into my basement. As far as I can tell, there is no return vent in the basement.

It seems a waste to me to be conditioning such a huge space that I don't really live in. But, I don't really understand too much about the reasoning for why certain areas in my home is conditioned. For example, I was told by an energy auditor that the crawl space under my bathroom should be conditioned (which also seems wasteful).


Why is there a supply vent in my unfinished basement?

Should the vent be opened and heating/cooling my basement?

1 Answer 1


Any area that contains water lines should be heated if temps hit freezing where you live. Crawl spaces without insulation should also be heated in these climates particularly if you have non-carpeted floors above them to avoid cold floors in the winter. Also, I'm not an HVAC expert, but I've been told you should condition the air through which uninsulated ductwork runs.

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    Additionally air conditioning typically does quite a bit for controlling moisture in addition to circulating the air. Keeping the air circulating and/or keeping moisture low is key in preventing mold, mildew, etc. Jul 22, 2015 at 17:28
  • @Josh you're right. That's exactly what the energy auditor said about the crawlspace: it would help prevent cold floors and keep the pipes from bursting. Maybe the cold floors is why the previous owners put carpet in a full bath. I found cureforthecommoncrawl.com , which has a lot of good information about crawlspaces. Jul 22, 2015 at 18:25

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