It’s 10 a.m. on a Saturday and I’m cooking an egg on the sidewalk, not in Death Valley but in St. Paul, and in a solar oven. The pace of solar cooking allows me to parent, write and ponder our civilization’s future without burning my egg. I am using no natural gas and producing no carbon dioxide in the process. But the sun is not always available and a crispy solar pizza is still a dream.
Using the sun wisely is not a new concept. About a thousand years ago, the Anasazi built pueblos under rock overhangs. In the best sites, the rocks shaded them in the summer, yet allowed the sun to warm their homes in winter. I love simple changes to homes that make them more efficient. Passive solar thinking, both past and present, help buildings use less and provide more. I would like to share solar projects that can make your home a little more energy smart.
Our attic can get very hot because of south-facing windows (and because heat rises). A springtime project hatched when I found canvas on sale. It was black on one side, white on the other, and CHEAP. I made reversible curtains that reflect light in the summer and absorb light in the winter. When we remember to close the shades on summer days, the attic is lovably cool in the evenings. Although we did not get much use out of the black side of the curtains in the heating season, since the sunlight felt so good in the winter. Yet, closing the shades at night prevented heat loss and drafts.
If you’re not the sewing type, gaiam.com has shades for the inside or outside of your window. The added benefit of exterior shades is how the light never enters the building. These shades cost about $70 for a double window and are left up during the winter.
Energy Saving Awnings
Another way to dial up the right amount of sun (and the heat that goes with it), is putting awnings on south- and west-facing windows. The Center for Sustainable Development at the U of M reported 25% savings on cooling costs for the average Minneapolis resident that added awnings to their home. Design awnings like the Anasazi did, so they keep out high angle summer sun and let the lower winter sun in, when you want the extra heat.
The awnings on our second floor windows keep direct sunlight out of the front rooms. This part of the house used to cook. Our pledge to avoid air conditioning this summer would be a lot tougher without these awnings. The awnings we got were pretty expensive but they’re also solar hot water collectors. I’ll save that story for another article. If you would like conventional awnings, expect to pay about $200-300 for a single window.
After about 25 minutes of writing this article, the black box that traps sunlight in my solar oven is 250 degrees F. It gets direct sun as well as sun from the reflectors. If clouds stay away, the oven should climb another 50 degrees, but my egg looks done, so I’ll take it out and leave you with these wise words: Using the sun wisely may keep you waiting or let you down at times but it will save money, improve energy markets and reverse some of our impact on the environment.
The best books on energy efficiency were either written thirty years ago or thirty seconds ago.
- Thermal Shutters and Shades: Over 100 Schemes for Reducing Heat Loss Through Windows, by William A. Shurcliff, Brick House Publishing Co., 1980.
Solar Oven Society
Rugged, durable solar oven option.
3225 E. Hennepin Ave.