Your just going to have to try it for yourself. In my center unit
townhouse I have nobody living next door, but I can turn off my heat
even on a very cold night and it never gets below 50 degrees.
Actually, the only time I really run the heat is first thing in the
morning, so I can step out of the shower into a warm room for a few
minutes. And my house has no insulation in it. I'm sure that having
a basement helps.