Here at Green ID, we typically tell people that adding insulation to your garage is an unnecessary home upgrade. Adding insulation to your garage will not save you money on bills. Of course, if you have rooms bordering your garage or above it then that garage wall should be insulated. Insulating the wall that separates the room and the garage will protect that room from being effected by the garage’s temperature.
If insulating your garage is more about comfort and less about savings then we completely encourage it! If you’re one of those people who enjoys working in the garage then insulating the space might be a good idea. Insulating the garage will help you keep the warm or cool air inside without it escaping and being influenced by the outdoor temperature. Just be aware that that tempered air will escape immediately when the garage door is opened.
Some homeowners will insulate their garages during construction because they know that they’d eventually like to turn it into a bedroom years down the road. This is a fine idea as long as you’re using insulation that will not deplete over time like microfiber or spray foam.
http://www.greenintegrateddesign.com/blog/is-insulating-your-garage-a-good-idea
