If you live in an older home, a good place to look for heat loss is around your baseboard trim. To see if this is happening, feel around your baseboards, between the baseboard trim material and the floor as well as between the wall and the baseboard. If you feel cold air, you can save some energy by sealing this up, which is very easy to do.

To seal around your baseboard trim, get a vacuum with a crevice attachment and vacuum out all the dirt between the baseboard and the floor as well as the baseboard and the wall. Then get some clear silicone caulking/sealant and apply it between the baseboard and the floor as well as the baseboard and the wall. This will help keep out cold drafts and help reduce your energy bill in the winter.