I’m glad I air sealed and tripled my attic insulation a couple years ago.
I just had a 30x60 ft pole barn built with a shop and man cave. 6-in walls and insulation and a wood burning stove heats it. I can do wood burning because I have about 25 acres of woods. I could heat that thing for 2 years just on the wood lying on the ground right now.
I am so glad I left Seattle for rural Kentucky 10 years ago. :-)