Air sealing….
1. Attic
2. Basement (sill)
3. Everything else.
Get the ceiling and around any upstairs windows first. You can easily hit the low hanging fruit with a foam gun and silicone. It’s amazing how much of a difference it makes!
Roger that!
Here's our problem in the basement....many fold (and that's where the woodstove is, but basement is only partially bermed on one side, other 3 sides have windows. Walk in door there too.
When we bought the house we discovered the 'basement' is finished. Nice looking sheet rock. Ceiling is also insulated (fiberglass bats), so it wasn't always a finished basement.
So problem number 1, I can't access the sill plate area
Wife says NO way we're pulling off all the sheet rock!
Problem number 2 and this is to me insanity. Walls of basement, e.g. the foundation, is concrete block poured full of concrete. Stout yes, but r-1 at the most. The builders put 2x4's sideways on the walls, then sheetrock and NO insulation! Absolutely insane.
Cellulose blowers want $3000 to blow (drill and fill) the basement walls with cellulose. At most I'd get is 1.5 inches. ....so R 2.5 maybe.
Companies used to drill and fill with polyurathane. But none are doing it anymore at least in my area
Speaking of windows. Last week all windows in the house (and one door) were replaced with Reliabilt/Atrium double pane/argon. 14 windows in all. That will help a lot. The window installer did a good job of sealing and insulating around the windows as he went.
I've learned (this house and the house we're selling) that air leaks just might be more important than insulation...I mean air can blow right through fiberglass.
But with all the problems the house has it does feel 'tight', well tight for a 1975 construction.....and I also base that on how often the heat pump (Heil dual fuel) comes on and off.
So that's view into my world.