John writes from Alberta, Canada: "I am building a house in Spruce Grove, Alberta, Canada where the temperature ranges from 30 degrees Celsius to -30 degrees Celsius and would like to know what the most cost effective amount of insulation to put in my attic, walls, and basement would be."

Answer: Your local building department will have the most accurate data on the best R-values to use for each of the applications you ask about. Thermal insulation levels must meet or exceed provincial or local requirements. Natural Resources Canada has a website for the Office of Energy Efficiency that may be helpful.