Note: This is NOT a question about how to insulate the crawlspace mentioned below. I already know what needs to be done there in the spring when I rip out the floor.
Onward:
45 yr old ranch. The whole thing's over a full basement except for a 10x8 part of the kitchen that's over a crawlspace. Who knows why - maybe it made the house cheaper to not extend the basement. Anyway, the only openings to the crawlspace are two 8" x 24" rectangular cutouts in the wood supporting the house. Just small enough to be useless. But, they're open to the basement and cold air's pouring in.Bought the place last September. It's well maintained, except I keep finding little things that make me wonder why nobody dealt with them before. For instance, there's no fiberglass batting stuck up between the rafters at edges of the basement. What I'm wondering, though, is if there's a good reason for those crawlspace gaps to be left open. Maybe to prevent moisture buildup in the space? Peering in with a flashlight, I can see that there's no plastic over the bare earth, no insulation of any kind (which is why I'll be attacking it in the spring).
I'm not trying to heat the basement, but it can't be good for the house in general to have that cold air coming in from the crawlspace. Any reason to leave them open?