Q: So your walls are insulated with 4″ fiberglass batting? Earlier I had the impression that your house has no wall insulation. What about homes much older that ’74 with NO wall insulation?
A: Yes our house has 2” by 4” stud cavity walls filled with fiberglass. The only answer, John, is to get wall insulation. You can do this without having to remove and replace all your siding by blowing in spray foam or dense packed cellulose from the outside. This requires drilling holes in the siding but these can be patched afterwards or a small section of the siding can be replaced. If you have no insulation today in your walls you are losing money through the walls the way that water runs through a sieve.