Heat it? In all seriousness, we'll need some details. Is the crawl space accessible and, if so, have you crawled it to check for insulation under the floor? Are you feeling cold radiate from the floor, or feeling cool air circulating? What is the flooring material and how was it installed (if you know)? How is the rest of the house heated/cooled and how is this room heated/cooled? Are any other areas of the home over a crawl space and not as cold? What is your physical location (nearest large city or region of state) and any quirks as to where you live (at elevation, in the depths of a forest, next to a glacier)...you get the idea, the more details, the better the possible responses.

There is no insulation in the crawl space. The floor is carpeted. The floor is cold & the air in the room is cold. No other areas over another crawl space are not as cold. We live in a wooded area w/ a rock out cropping. Hope this helps you. Thanks.

What do you recommend to heat a crawl space?

OK, so:

-Are the other areas over crawl spaces over the same crawl space or another, and is the underside there insulated?

-What is the means of heating the space, and is it the same as the other spaces?

-Are you in a cold climate or moderate climate area?

The cold air in the crawl space is meeting the warmer interior air and surfaces and cooling them. This may possibly causing condensation on the underside of the flooring and on the joists and lead to mildew and/or rot. The moisture level is often A huge secondary issue, especially if the crawl space is dirt or gravel floor.

You really don’t want to try to heat a crawl space unless you are in a cold climate. To heat the crawl space, you would be looking to seal it and add it to the current house climate control envelope, a big job. It involves several stepping including insulating the exterior crawl space walls, sealing the entry points, and providing a circulating heat source and moisture control.

In a moderate climate, the usual approach is to thermally break the floor from the crawl space, normally done with insulation. You would install insulation on the underside of the floor, and then a vapor barrier. The best insulation, closed-cell foam, combines the two, but is the most expensive. The use of fiberglass insulation without a vapor barrier is doomed by the moisture in the crawl space, which will just increase the moisture issues to damage the flooring and lumber.

If the room is ”under the crawl space”, that would explain cold air seeping in. Otherwise, why not address the root of the problem before adding recurrent costs.