Increasing Garage Door Efficiency
Entry doors leading from or to the garage sometimes had doors installed that were intended for interior use only. Without proper insulation or weather stripping, an interior door installed as an exterior door will cause significant energy loss.
Interior doors are usually either paneled wood, or hollow core doors. While paneled wood doors can be used in many cases as exterior doors, the door will still have to have air seals installed around the door and a door sweep seal installed on the bottom of the door.
Hollow core doors are two, thin veneer panels that sandwich corrugated cardboard. These doors are very flimsy and provide no R-value to prevent cold from penetrating the door. Adding seals to a door of this nature will not work because the door flexes so much as it is, and there is very little solid backing to allow for seals to be attached and actually stay.
A good quality exterior door has polyurethane insulation as the core of the door. The exterior is usually stamped in a 5 or 6 panel fashion for character and is made of steel. These doors also have a 20 minute fire rating which may be important if a fire were ever to start in the garage. This is very important as over 70% of all house fires start in the garage.
Exterior doors cost roughly $500 to $1000 depending on the insulation and hardware you choose. Remember that the door must NOT have a window if going between the house and an attached garage.