Double Glazed Patio Doors

In many modern homes, the largest window in the house isn't a window. It's the sliding door that affords access to the patio or deck in the back. Sliding patio doors became popular in the 1970s, just about the time that double glazing came into popularity as a means of controlling energy costs and heat loss. By using double glazed windows in the door, the use of sliding patio doors became an energy conscious decision.

Double glazed patio doors sandwich a layer of air or inert gas between two layers of glass. The layers are separated by a 'spacer' that holds them from 12-26mm apart, and seals the perimeter between the two to prevent moisture and condensation from compromising the lowered heat conductivity. The use of double glazed windows rather than a single pane of glass can reduce the heat lost through a window by as much as 50%.

The classic double glazed patio door consists of two large double glazed windows hung from a set of rollers in a channel, and set into a sliding channel at the bottom. Most of the older ones are framed in aluminum for strength - the size of the windows makes frame strength a priority. As it comes time to replace many of the doors that were first installed in the 1970s and 1980s, many people are opting to remove the channel and sliders in favor of more attractive French doors.

Replacing worn patio sliding doors with new double glazed patio doors offers numerous advantages. First, both the materials and the manufacturing process for making double glazed windows have advanced considerably in the intervening 35 or so years. The new generation of double glazed patio doors is far more effective at insulating your home and reducing heat loss through the glass. The use of PVCu in frames makes for far lighter doors than either aluminum or wood, and PVCu has better insulating properties than aluminum. I have rather vivid memories of the frost forming along the top and sides of the aluminum window frame of our patio doors when I was a child. PVUc frames make that a thing of the past.

Besides better framing material, the glass itself has changed considerably. Today, you can choose low-e glass for your double glazed patio door. The coating on the inside of the glass substantially reduces heat transfer between the inside and the outside. The use of a desiccant in the sealing strip spacer between the panes in double glazed windows is another innovation that helps create a more durable window. By completely drying the air between the two panes, manufacturers reduce the likelihood of moisture condensing inside the window. Finally, by choosing double glazed patio doors that are filled with argon or another inert gas rather than air you lower the heat conductivity of the windows still further.

If you choose to replace your old sliding patio door with a new French window, there are some marvelous new innovations. Look for folding double glazed patio doors that can be used to replace entire walls, French doors with headers and side rails, or French doors with fanlights and mullions that add style and elegance to most any facade.