Oh, boy, This subject has been discussed here a few times too, see the archives, I'll bet you will be reading for a while.
Al and I were contemplating running with the furnace on this year when we leave here right after Christmas. Now I am re-thinking the situation.
We frequently run with the frig on, but have no qualms about food spoilage and sometimes run with it off.
But, this time we are taking my plants with me, and there is gonna be a problem getting them into the truck, and I had hoped to run with the furnace on low. I know Steve R. does this in cold weather. We did do it one day last year, when it was about 12 degrees and we were about 2 hours from our stop for the evening, we turned on the furnace, have to say, it sure felt good going into Montana and having it a bit warm.
So, Back to plan A or B or Q, R, S???? Guess I will get my creative juices warmed up (HA HA HA HA, it is 21 here right now and 12 to 16 inches of snow on the ground) and see what I can come up with.