According to Energy Star, every 1 degree increase in temperature will cause a 2.25 to 2.5 percent increase in energy usage. That means that a garage refrigerator will use 45 to 50 percent more energy in a 90-degree garage than in a 70-degree one.

Bottom Line
Use an energy-efficient refrigerator in a hot garage if you truly need the additional storage space. However, you will keep energy usage down even more by making do with the kitchen refrigerator.