The cost of high-quality glass patio doors can be prohibitive and a door of lesser quality may not stand up to the constant use of a large family. While aluminum doors are seemingly the least expensive, they cannot be adjusted should the house shift with temperature changes. Metal door frames accumulate frost in cold climates and can build up to the point that the door won't open.
Sun Damage to Interior
Depending on the location, the sun's heat and light can damage or fade floors and walls directly in the sun's path. Insulated draperies fade fast and are expensive to replace.
A glass patio door allows quite a bit of heat to come in or go out, depending on the season. The loss of heat in cold climates can be substantial and the amount of heat that comes in can be substantial in warmer climates. Patio doors with special efficiency ratings that significantly alter these losses and gains are more expensive. Condensation on the glass can cause mildew on wood surfaces that is difficult to remove.
While it may be tempting to purchase a less expensive door and an off-brand, keep in mind that seals between the glass panes break, causing cloudiness, screws come out and disappear, and screen doors need repair or replacement. Be sure that the company can guarantee the availability of parts should you require them.
While the glass on patio doors is easily cleaned inside, the outside temperatures have to be above freezing. The tracks that sliding doors use accumulate dirt, dust and bugs, all of which can build up, making it hard to open and close the door.