And thank goodness we have a well insulated house. If you have an old house, and many of you do, those things can keep heat like a sieve as apparently they didn't believe in insulation in eighteen-blah-dee-blah. Or they did believe in it, as the void between the walls. Insulation is horribly unsexy, so it is possible when a 100 year old house gets flipped or renovated by an absentee landlord, things like insulation (and newspapers stuffed into crevices don't count) get's skipped because you can't see it.
The houses on my row were all built at the same time, so talking with some neighbors, seeing some renovations and my own experience tells me, these houses were built with no insulation. When I renovated my house in 2007 I had fiberglass stuffed everywhere, except the party wall between us and B & IT. Another neighbor, when renovating used the foamy stuff. The only problem with that is it can over expand. Other neighbors in rentals that haven't been gutted have to freeze or blast the heat.