Adding spray foam insulation to your garage will keep your house warmer and it also allows you to get into a warmer car on freezing winter days. A lot of garages do not have insulation at all, and most builders cut costs by not adding insulation in the garage when the home is initially built.
Bonus rooms floors above garages are typically insulated with fiberglass insulation. Fiberglass does a poor job of keep those floors warm. When the first cold front comes, we get many calls each fall about these cold floors. In many cases, we see frozen pipes in these floors due to the poor performance of fiberglass insulation. Since spray foam is both an insulation and an air seal, it works better in these areas.
Insulating a garage with spray foam will keep it warm, and in most cases keep it above freezing without the need for a furnace or a heat source. Wouldn’t it be nice to get into a car that is 50-60 degrees rather than a car that was in a garage well below 32 degrees?