My house with some 16 sear dual stage units and foamed insulation in wall and roof with brick and stone on top is really comfortable at 76. My 12 yr old daughter wears a coat in the house all summer. I do go to 74 at night, but need sheet and comforter with the ceiling fan on low.
Winter is comfy at 69, same sleeping arrangement as above, less ceiling fan.
My power bill last month was $176 for a 4900 sq ft house.
Now that the house is under contract, been in a lot of 74 degree houses that make me sweat.
Foaming the roof is the first thing when I move in to new place.
Had to keep it at 74 in our old place or it was too damn stuffy. Our new (to us) place gets chilly sometimes and it's kept set at 76 constantly. Our new place doesn't have cathedral ceilings like the old, and has a metal roof and new a/c. Must make some difference.
There's not a magic temp on a t-stat. Depends on location of thermostat, vents, sun, return. You just have to find your comfort temp. It is nice to save money but I go by what I heard my dad say when he had this argument with my mother about 25 years ago. If I'm going to sweat to save money we'll just turn it off and save enough to matter. Otherwise we're wasting every penny we do spend to save maybe $20 a month and that's just stupid.