- new or existing;
- type of heat (oil, gas, electric);
- location, location, location
Playing with the Insulation Calculator was educational. For my ZIP code, they recommend R-38 in attics where the fuel is natural gas; oil or a heat pump but R-49 for electric or LPG [Liquid Propane]. For all new construction, they're recommending R-49.
The contractor said it would take one day to "install" the additional insulation, and they were finished on schedule yesterday. Now I can wait for my energy costs to drop like a rock, right?