Insulation protects the home against excessive heat loss due to heat flow. Heat flow describes the phenomenon by which hot air naturally flows toward cold places, such as an attic or even through uninsulated surfaces to the outside. Properly insulating a home helps keep living spaces warm through the coldest months. Though insulation traditionally goes in places like attics, walls and around ducts, you can put insulating material almost anywhere to keep heat within the home, including in or on garage doors.
R-value expresses an insulating material's resistance to heat flow. The higher the R-value of a material, the better it insulates. Various factors affect the R-value of insulation, including the material used and its thickness and density. R-values run a large gamut, from fractional values to well into the 40s and even 50s. A complex mathematical formula exists for calculating the R-value of a substance, though nearly all commercially produced insulators come with R-value ratings from the manufacturer.
Garage Door Insulation
Garage door insulation assumes one of two primary forms: It either constitutes a part of the door's construction or an additional element added to an existing door to increase its insulating value. Standard insulated garage doors offer an R-value ranging from 5 to 10 or 11. You can purchase garage doors with R-values of 12 or higher for increased insulation. Old or free-standing garages or those built in typically warm areas sometimes contain no insulation at all.
Garage doors with R-9 insulation keep more heat within the home than garage doors with R-6 insulation, though they usually also cost more. Before purchasing a garage door or insulation, consider your needs. Free-standing garages relate in no way to the temperature in the home. You only need optimal insulation for a free-standing garage if you need to keep the inside of the garage warm. Attached garages require optimal insulation only if no insulation protects the home from the garage. Consider why you want to insulate your garage door and how much protection you need. R-9 provides more protection than R-6, though more is not always necessary.
Various types of insulating materials exist for garage doors. Consider the positive and negative aspects of materials before purchasing insulation or an insulated door. If you predict you need R-9 insulation for cold periods of the year but not all the time, look into a door with removable insulation panels. Garage doors made from plastic, vinyl, aluminum and fiberglass contain insulation within the door. If you need year-round insulation, these doors provide optimal performance, though you cannot change the level of insulation within them; determine whether you need R-6, R-9 or any other value before purchasing such a door.