Apropos nothing, I once was renting a guy's basement. It was always uncomfortably cold, but there was a gas space heater, but all of the warm air, of course, floated up to the ceiling (which was the underside of the floor of the upstairs), so my feet would freeze, while my head would sweat. In lieu of walking around the apartment on my hands, I took one of those little fans - you know, the shaded-pole motor, with about a 3" (8 cm?) aluminum fan blade - and hung it from a joist to blow warm air downwards toward my bed and stuff. It went "THRUMMMMM!!!!" and my roommate/landlord didn't like the noise. Well, it turns out that he also had an old turntable (remember record players?) that he was going to toss, so he let me salvage it, and I took a couple of the suspension springs from the turntable, and hung my little fan from them. The silence was golden. :-) :-)
Floors make surprisingly good sounding boards. :-)
Good Luck! Rich