Progress Report: Energy Efficient Windows

I’ve mentioned this before, but I’ll state it again for any newcomers (or those of you who may have forgotten): Our home is being built based on a passive solar design. Because of this, windows are an important element to reduce our heating, cooling and lighting needs. In order to maximize solar heat gain in the winter, our major glazing area faces south to take advantage of the sun in the winter when it’s low in the sky. The roof overhang was designed specifically to avoid excessive heat gain in the summer when the sun is high. You’ll notice both of these features in the photo below. (Note the windows just below the roof line that are barely visible.)


Window size and frequency is just as important on the east-, west- and north-facing walls. The photo below shows our north-facing wall. The windows on this wall are smaller and fewer than those on the south wall, on purpose. As our house sits, much of the winter winds come from this direction. Also, north-facing windows take in little solar heat. Therefore, they will mainly be used to provide ample daylight in back rooms of the house.


Our windows have a low-emissivity coating on them, which means they are a bit more expensive than regular windows, but according to the U.S. Department of Energy, they reduce energy loss by as much as 30-50%. They also meet or exceed Energy Star guidelines.

Originally, we were going to install Marvin windows in our house. But when we compared the Marvin/Pella windows side-by-side, we realized we could get the same quality windows for a heck of a lot cheaper.

I was also pleased to see a whole section on Pella’s Web site dedicated to their “green commitment.” Here’s what they say they are doing to help the environment:

• Recycling — Pella’s process minimizes our use of nonrenewable resources.


• Responsible Procurement — Pella uses sustainable sources and works with vendors who practice responsible harvest and replenishment.


• Pollution Minimization — In 2006, the EPA recognized Pella with its Pollution Prevention for Environmental Excellence Program honorable mention award for our responsible manufacturing processes.


• Reducing Energy Consumption — Pella offers the windows and doors rated #1 for energy efficiency among top national brands.

The company also claims to be FSC certified, offering the option of windows and doors made from wood certified to have been harvested from well-managed forests.