[maximusbravehea]

My brother-in-law insulated his master area separately for sound attenuation. Walls & ceiling (2 story).

If you have zoned HVAC it would help if you "live" in one area and don't condition the rest of the home as much. I guess you could have even a 20-30F difference if you were REALLY into saving utilities.

I remember in Columbus OH, students would rent these huge old homes about a mile or 2 off campus. They would say how cheap the rent is. Then the winter gas bill would come in the multi $1000s. Zero insulation in the walls. Gas cost is much higher now than in the 80's. Wonder if the landlords ever invested in insulation... kind of shady to do that to people!