31 ways to save on winter heating for $30 or less

Blankets between rooms can hold heat in a smaller area.
Or setting an old jacket along the bottom of an outside door.

Using heat tape can keep from heating the whole area they are in.
And even though many of the heat tapes are temperature regulated.
Putting the heat tape on a timer can reduce the power used. On for a half hour, off for 1 1/2 hours will often keep them from freezing.
On real cold nights it might need changed to on for 1/2 then off for an hour.
Makes the heat tape last longer too.

I have plastic on the outside of the whole west wall in my drafty old house.
Black plastic lasts way longer in the sun.