Nat gas water heat and furnace. Just had the furnace and ducts cleaned before winter and my bill for last month was ~175. That hurt a bit, but I have seen similar in years past with a smaller less efficient home (we just moved).
The furnace in the new home is about 5 years old (95% efficient). It cost roughly this much last year in the aforementioned house (650 square feet smaller and no basement). We also have more windows in the new home, so that hurts the heating bill a bit also.
My next task is to remove all the window trim and re-insulate around them with spray foam, but it takes time to get that done. There are a number of things you can do to help, but dang you’ve got me beat pain-wise the way it sounds.
Good luck to you!
Careful, be sure to select a foam with minimal expansion. The garden variety expands too much and may cause problems, including windows that won’t move. You may also void any warrantee from the window manufacturer.