Hi typically it’s 14F to -5F here in the winter but we had 3 weeks of -40F in January last year. I like the point about selling my pellet stove eventually, as this is my first home and I don’t plan to keep it forever, I’d like to move out of town.Couple thoughts -
Pellet stoves: get a Harman and the biggest one you can afford. You can sell all day long if you ever leave.
Pellet heat: what is the temperature range in your area? If I lived in Canada, I would look at pellet furnaces and not a stove.
Before spending $5K: If your temperatures are only heading to -15 F, then I would go electric, high efficency mini splits. Mitsubishi's HyperHeat runs 100% efficient at -15. Panasonic has models going down to -30 F. They are not rocket science to install. Costs might be $2.5K more installed, but guess what, no buying nor hauling pellets
Natural gas: do you have access to a line? If so, I would go natural gas furnace.
Insulation: how much cubic feet of insulation do you need? A can does 12" x12" x 4". Next size up looks like an expansion tank, doing 50 cubic feet, usually sold in pairs online, totaling 100 cubic feet. Next would be to get a company to come in and do it for you. Easiest thing to do is drill 1/2" holes where you need the foam, fill, take a sheet of drywall do a 1" hole, then use the 1/2" bit to keep the paper on the 1" side. Patch with mud on the wall and tape. You'll breeze through it in no time. Be forewarned, taking foam out of walls where you may, in the future, run electric becomes very cumbersome. Get your wires in now
the reason I decided against pellet or NG furnace is because the ducting was quoted to me at 5-7K plus the cost of the furnace so pellet stove was more affordable. NG is also veeeery expensive here and people supplement their NG with pellet heat. I don’t have a NG line to my home so it would be pretty expensive to change into a gas system. I will look into the mini splits I haven’t heard of that! I am getting my pellet stove (P68) installed tomorrow morning though so it will be for educational purposes.
I like the extra insulation idea! I will definitely look into that too. Thanks so much for all the helpful information