Growing up we had a coal furnace in the (basement) cellar. That is not something to be started up early in the fall. What I remember the most was the mornings when my Mother would turn on the kitchen oven and it was so warm getting dressed. This kept the furnace off for at least a month. Never had air-conditioning. BTW, if you are renting the landlord has to put the heat on from 10/15 to 5/15.
I own so use whatever I want.