We've been on an annual budget plan for years where they bill you a fixed amount each month, and then we ante-up any overage in July and they issue an adjusted rate for the next year based on current cost. My monthly was $182/mo. but now it's $454/mo. effective July. Our boiler uses oil for both hot water and baseboard heat, and it's not like we can just rip it out and replace it with all-electric stuff without a huge outlay.
I'm really torqued over this. If you're a heating oil consumer, prepare yourself to take it in the rear.
Also depends on the efficiency of the furnace, and tech used in it. For a while there it was considered cheaper to run the furnace at lower power, but near constantly vs. It going full bore for a while, then shut off, then blast, then off.