I have an old rental property in Statesville NC.
I plan to put in central heat/AC. Trying to decide between propane gas pack and heat pump. The contractor recommended adding insulation and replacement windows.
I plan to get blow in insulation in enclosed walls. Have a bid for cellulose.
And battings and blow in for accessible attic areas.
The real question is windows. I could put in replacement windows at about $214 per window installed. But I don't see them paying off. The U factor is .37.
But the U. factor for a storm window over and old window is .6 according to this site:
I did some calculations and I just cannot see a replacement window saving more than $10 to $15 per year based on those U-factors. Probably less since I assumed a 50 degree F differential for 180 days per year which seems a bit high and I used $20 per million BTU of heating/cooling cost and 12 square foot window.
214 per window, vs unknown storm window cost and installation time.The rental is about 3 hours drive so I do have to go to some trouble to travel down and install storm windows.
It will cost around $4000 if I go with replacment windows.