Exterior Door Replacement

Modern exterior doors often fit and insulate better than old ones. Consider an insulated metal or fiberglass door when replacing exterior doors. They are a better investment than wooden doors since they are much more durable, have lower maintenance needs and seal and insulate better. They also have the added advantage of offering more of a deterrent to intruders.

Most insulated door prices range from $200 to $400. One common type has a steel skin with a polyurethane foam core; they usually have a magnetic strip (similar to a refrigerator door magnetic seal) for weather-stripping. If installed correctly and, if the door is not bent, this type of door needs no further weatherstripping. The R-values of most steel and fiberglass clad entry doors range from R-5 to R-6 (not including the effects of a window.) For example: A 1-1/2 inch (3.81 cm) thick door without a window offers more than five times the insulating value of a solid wood door of the same size.

When you buy a door, it will probably be a pre-hung frame. Pre-hung doors usually come with wood or steel frames. In most cases, you will need to remove the existing door frame from the rough opening before you install a pre-hung door. The door frame must be as square as possible, so that the door seals tightly to the jamb and swings properly. It is a good idea to use expanding foam caulking to seal the new door frame to the rough opening and threshold to prevent air from getting around the door seals and into the house. You should do this before adding the interior trim. Apply expanding foam carefully, especially with a wood frame, to avoid having the foam force the frame out of square.

Glass or "patio" doors, especially sliding glass doors, loose heat much faster than other types of doors because glass is a very poor insulator. Most modern glass doors with metal frames have a "thermal break," which is a plastic insulator between inner and outer parts of the frame. Models with several layers of glass, low-e coatings, and low conductivity gases between the glass panes are a good investment, especially in extreme climates. Over the long run, the additional cost is paid back many times over in energy savings. When buying or replacing patio doors, keep in mind that swinging doors offer a much tighter seal than sliding types.

A sliding glass door's weatherstripping is intended to reduce air infiltration. However, by the sliding nature of the door's design, it is impossible to stop all the air leaking around the weatherstripping while still being able to use the door. Also, after years of use, the weatherstripping wears down and air leakage increases as the door ages. If the manufacturer has made it possible to do so, replace worn weatherstripping on sliding glass doors with new weatherstripping.