Sliding patio doors are very popular in my market. Thier large glass panels allow us to view the outside. They open and close without needing floor space and are simple to operate. But they have a dark side…
They aren’t the most energy efficient. If you caught my recent post on Instagram, you’ve seen this photo already. This new sliding patio door came from a very popular manufacturer of windows and doors. They have adjustments to raise and lower the operating panel, but there is no adjustment to push the fixed panel and operating panel closer together to improve air leakage, which this door has. The purple “fingers” between the fixed and operating panels is cold air (0°F at the time of this blower door test) being drawn across the fixed glass panel.
Here’s another I took a few years ago, this door was not installed correctly and needed some adjusting, I wasn’t operating the blower door when I took this photo, though it looks like I was.
And one more, a problem with the track and lower seal area of this sliding patio door. This location is usually where I see the most air leakage during blower door testing. The home’s indoor temperature was around 70°F at the time of the photo, the area near the door track is much colder, cold enough for the wood to become a condensing surface.
My advice, if you’re trying to build an efficient or high-performance home, avoid the normal sliding patio doors. The “French” style patio door is slightly better, they latch against a door seal providing better performance. If the sliding style door is needed, after all, they don’t take up any floor space when operating, look into the lift and slide style door.
This is a quick video I took at Jake Bruton’s home of his Schuco 12-foot lift and slide patio door, this door features an eight-foot fixed and four-foot operating panel. That large handle lifts the very heavy door slightly allowing it to easily slide, when the handle is in its up position, the door sits down on a seal, greatly increasing air tightness of the unit. This style door is a big upgrade over a standard sliding patio door, and the cost will reflect that.
Rember, operating windows and doors will always be less efficient than a fixed window. A fixed window will be less efficient than a wall without a hole in it. Choose wisely.