My house is built in 71 and had single pane windows and real poor blown in insulation. After changing both I dropped my gas bill down ~100 a month and cant wait till this summer to see the electric bill come down. Insulation is greater than the windows on my home and I would check that first. About 2200 sqft place heating it wih bad insulation and windows costed me around 180-200 a month (single story) with a 90’s york central heater. Now with my tankless and upgraded windows/insulation my gas bill is average 80 a month.

When I run my pool heater to heat the pool to 102 degrees and float in the pool drinking (40-50 degrees outside) while watching hangover on the projection screen on side of house my gas bill shoots up to 300 that month. Hey it seemed like a good idea at the time 😉
Maybe you can call me a “ratard”.

That was about midnight one night. The neighbors love me.