"It’s not bad at all!! We have 6 separate central a/c units and 8 separate central heating units. We can pick & choose what parts of the building to heat/cool and to varying temperatures. Our highest gas bill this past winter was $330 and that included almost an entire month of subzero temperatures. The building is incredibly well insulated."
https://www.reddit.com/r/mildlyinteresting/comments/e4r2ap/m...