There's a lot of talk these days about installing new energy-efficient windows. Thanks to a Federal tax credit of up to $1,500, window advertisements, both print and radio and TV broadcasting, are aplenty. I don't want to knock energy-efficient windows. There are some great window products available. Some even rival the overall performance of walls, that is, if you account for the heat energy that enters the home via sunshine, depending on the climate and orientation.
What I would like to talk about here are window shades. My wife and I bought our house 19 years ago. We are only the 2nd owners. The house has double-pane wooden windows made by a major well-known manufacturer. No low-e coating. No argon gas filling. But the windows were in excellent shape when we moved in. Instead of replacing them, we decided to install energy-efficient window shades to improve their thermal performance. After all, we would need to purchase some type of window shade for privacy and darkening anyway, even if our windows were of the highest efficiency.
One of my colleagues in a solar energy group I belonged to was a distributor of a high R-value quilted roller window shade. We had these installed on many of our windows. We went with a less expensive non-roller version for one bedroom window and a little-used door in our downstairs. This lower-cost version doesn't have a cord and doesn't roll up like the others. It closes with Velcro on the edges and bottom and you fold it up once or twice and attach it to grommets at the top, with additional ribbon ties.
All the window quilts have two layers of polyester batting, an inner reflective vapor barrier, and a cover fabric that came in several colors and designs. According to the manufacturer, in the winter a double-pane window (R-value 1.8) increases to R-5.51 with the window quilt, for a 67% savings; in the summer the shading coefficient of a double-pane window increases from .88 to .82 with the window quilt installed, amounting to a 7% savings. Seals all around the windows seal against drafts and prevent convective air heat loss. We chose blue window quilts for the bedrooms and a bathroom, a peach low-cost one for the guest bedroom, and white window quilts for the living room, den, dining room sliding glass door, and downstairs door which we never use. Some had to be custom-made because we have two or three standard windows adjacent to each other, making them very wide, and a tiny window in the bathroom.
Are we happy with the window quilts? Definitely. They are very easy to roll up and roll down. A valance covered with the same cover fabric hides the rolled up quilt. Any reservations? If we knew then what we know now, we probably wouldn't have installed them on the tiny bathroom window. The quilted shade is small and too lightweight to roll down simply with the cord. We have to also pull it down. It's also prone to some mildew—my wife believes in keeping the steam in during a shower to clear up the sinuses, before turning on the exhaust fan. When it gets cold, the quilts keep the heat in over the winter, but this also keeps the window panes cold. When we open them in the morning there's always a lot of condensation on our bedroom windows. We also probably would forgo placing them in the bedrooms that are constantly used. I suppose we give off a lot of moisture while sleeping, and the moisture seal isn't perfect—I may need to replace the foam seal at the bottom of the quilt, a very simple, inexpensive procedure.
John Lippert is an employee of Energy Enterprise Solutions, a contractor for EERE. He assists with technical reviews of content on the Energy Savers Web site.