Stellar Insulation's goal is to keep each house properly insulated. You need to insulate your home when 1) your home is too cool in the winter and too hot in the summer 2) Your energy bill cost more in your older home than newer energy efficient homes. 3) when your attic insulation is less than 10 inches thick. The effectiveness of insulation is commonly evaluated by its R-value. However, an R-value does not take into account the quality of construction or local environmental factors for each building. Construction quality issues include inadequate vapour barriers, and problems with draft-proofing. Get a $150 rebate from PG&E for 1,000 square feet of qualifying attic insulation, and $500 back for 1,000 square feet of qualifying wall insulation upon qualification from PG& E.