Storm doors for sliding patio doors
Have sliding patio doors that face south. On a sunny winter day, I turn off my heat and the sun’s heat coming through my doors heat up my home (Maryland). But when the sun is not shining, I lose so much heat. Closing the drapes cuts down on the heat loss a bit. Can you recommend a sliding glass storm door that will help keep us warm in the winter? The storm in one room must go inside and the storm in the other must go outside. Both doors are double paned. One is about 25 years old; the other about 15 years old. Do you have suggestions for the frame material (is aluminum suitable to keep the cold out?) and the glass (low e, hard coat or plain glass)? In the summer, the heat gain is not that bad, so I am hoping for a suggestion that will maintain my winter solar heat gain and keep the cold air out. Thank you.
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Replies
I would suggest an air-tight quilted shade, such as Window Quilt that rolls up into a transom and slides down in a track.
Less expensive and more effective than a sliding storm (if you could even find such a thing), and it can be used both to keep winter heat in and to keep summer heat out since it incorporates a radiant barrier.
http://www.windowquilt.com
Q. "Is aluminum suitable to keep the cold out?"
A. No. The next time you buy a patio door, choose one with a fiberglass frame.
Thank you both for your good suggestions. I was hoping for a sunny solution. After posting my question, I found Mon-Ray which makes an aluminum frame sliding glass storm door and they can do it with clear glass. But after reading posts here, I wonder about the effectiveness of the aluminum frame for a storm. Have you had experience with Mon-Ray?
Carol, clear double glazing in an aluminum frame is what you have now, so why would this be any improvement? Aluminum frames are notorious for cold bridging.
Glazing with a low-E coating would reduce heat loss when the sun isn't shining, but the most widely available low-E glass is optimized for warm climates where solar heat gain is not desirable. That means you would likely be disappointed in the lack of heat gain on sunny days. This is probably why Robert suggested adding a quilt over the glass doors you have, because it could be counterproductive to replace them with better insulated doors that no longer give you the heat gain you have enjoyed.
Actually, I recommended the Window Quilt because it would be a waste of money to install a storm with a conductive frame over a sliding door with a conductive frame. The heat conduction through the aluminum frame eliminates almost all the benefit of the double glazing.
Your best solution, albeit costly, would be to replace the doors with new, quality patio doors with insulating frames and better glazing.
Pella offers both aluminum-clad wood and foam-core fiberglass sliding doors, with three glazing options: Advanced LowE (probably best for your climate) or SunDefense (both of which qualify for tax credits), and high solar heat gain Natural Sun (which does not qualify for the tax credits). They are excellent doors and will give you many years of pleasurable use. There are, of course, other brands that are both less and more expensive - but generally you get what you pay for.
Thanks, Robert, Martin, and Thomas for such detailed and helpful advice. I'll be comparing the Window Quilt to the Pella door, now.