We have an old sliding patio door. It gets chilly near it during winter and hot during summer. It is often drafty and outdoor noise comes through. What should I replace it with?—Ron A.
In a home of average efficiency, that old sliding glass door can waste more energy year-round than all the walls in that room combined. The heat is lost during winter and gained during summer as a result of air leakage and conduction losses through the glass itself.
Besides losing energy directly through the door, this inefficiency can make you set the thermostat higher during winter or lower during summer to stay comfortable, raising your utility bills.
There have been tremendous improvements in energy efficiency, security, and styling of replacement patio doors. Some of the new high-tech glass in these doors has an insulation value as high as R-10 in the center of the glass. It has special coatings on the glass surface that reduce heat transfer and block the majority of the sun’s fading ultraviolet rays. This can extend a like-new appearance and the actual life of your carpeting and furniture.
Many homeowners have told me that the first thing their family notices when a new efficient patio door is installed is the reduced outdoor noise. Much of the noise comes through the glass panes, but a significant amount also comes from around the frame and seals. Resilient weatherstripping greatly reduces air leakage, and multi-pane glass—with heavy inert gas between the panes—blocks sound.
Although any type of efficient replacement door can be installed, most people replace an old sliding glass door with either another sliding door or French doors.
Hinged French doors are more stylish. Hinged doors close on a compression weatherstripping seal, often making French doors more airtight. Sliding doors rely on noncompression types of weatherstripping. Even though it is not as airtight, it will be better than your existing door.
French doors are easy to swing open, but require a large area for clearance. A sliding door just slides in its track, so it requires no clearance. Sliding doors also provide a more unobstructed view. There is a little more maintenance on a sliding door to keep its track clean so it opens and closes easily.
Most door manufacturers allow you to order almost any type of glass. The best type for your home depends on factors such as your climate, orientation to the sun, and natural shading. In general, the minimum efficiency level you should select is double-pane glass with a low-emissivity coating and argon gas between the panes.
Even more efficient, but more expensive, is triple-pane glass or double-pane glass with low-emissivity plastic films stretched between them. Selecting optional krypton gas instead of argon gas in the gap between the panes improves efficiency and reduces outdoor sound.
The frame material is also important for efficiency and smooth operation. A pultruded fiberglass frame is strong and stable. Its strength allows for narrower frame profiles and more glass area. Fiberglass frames can be ordered with a real oak wood veneer on the indoor surfaces. The exterior is painted.
Vinyl door frames reinforced with internal steel supports are good insulators, maintenance-free, and reasonably priced. Solid wood frames are attractive and strong, but require regular maintenance. Choosing one with exterior vinyl or aluminum cladding minimizes this maintenance.
The following companies offer efficient patio doors: Champion Window, (800) 875-5575, www.championwindow.com; Fibertec, (888) 232-4956, www.fibertec.com; Peachtree, (800) 732-2499, www.peachtreedoor.com; Simonton, (800) 746-6686, www.simonton.com; and Weathershield, (800) 222-2995, www.weathershield.com.