Generally speaking, adding insulation to a home in Idaho alone does not significantly help keep a home cool in the summer, but when paired with air sealing and radiant barriers, it can have a dramatic effect on the comfort and energy efficiency of the home.
The majority of the unwanted heat in the summer is radiant heat. The radiant heat travels through the roof and windows heating up the home. The second largest source of unwanted summer heat is air leaking into the home. This is not just the little cracks by a window or door but rather larger construction flaws hidden in the attic and crawlspace. These flaws allow hot summer air into the home and are the equivalent to leaving a door or window open. The upstairs of a home can be just as comfortable as the downstairs without adding a window air conditioning unit. By air sealing and adding a radiant barrier, you can counteract the heat leaks.