CAROLYN'S BLOG ABOUT THE HOUSE CONSTRUCTION
AND THE YEARS BEYOND
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Sun, Feb 20
7:00 am

Passive Solar Design: When I began studying natural building, it took me awhile to get my thoughts around the idea that a house can be a heating/cooling unit, as well as an attractive shelter. I love visiting the cliff dwellings in the Four Corners area and seeing how the ancient people knew this. You will only find cliff dwellings on south-facing slopes. That is one of the core principles of passive solar design - large south-facing windows, or in the case of my house, a south-facing sunroom. (In the southern hemisphere it would be opposite, but I'll talk northern hemisphere.) The angle of the earth in the winter makes the sun go south, so it can shine through these windows and warm the house when you need it. Then, as the earth tilts in the hot summer, the sun goes north, so these windows are in shade. Obviously, this doesn't work so well near the equator, but you don't need the heating and cooling there.

As with south windows, much depends on your environment and climate. No matter whether you have double or triple pane windows, they probably won't be as well insulated as your walls. So, for that reason, consider how much south window area you really need. In the Sonoran Desert, we don't generally need much heating in the winter and we get really hot n the summer. I built a large sunroom, after moving here from New York, and as much as I love the natural light in the house and the feel of the sunroom, it is more window-space than I need. The good part is that I can shut off the sunroom on cold nights or hot days by closing my (double-pane) french doors. If your windows face right into your main house, you can't do that as well, so you will get the cold of the night beating at your windows or the heat of the summer. Plus, the sun bleaches out carpets, drapes, furniture. I use those inexpensive Emergency Blankets found in camping stores to insulate my sunroom windows in the summer. I have cockatiels in an aviary in my sunroom, so I try not to let the room get too hot or too cold. Those Emergency Blankets work incredibly well. I just tape them onto the glass and then cover them with bamboo roll-downs. If you've ever used them camping on cold nights, you will know how well they work. (As a side note, I am trying them in the garden this year, too. I heard the reflection confuses the bugs and keeps pests off the plants. I'll let you know how that works.)

If you live in a cold climate, then you would want thermal mass in your walls and in your home, so it all heats up from the sun and holds the temperature. Then do whatever you can to help the house hold that temperature overnight. Thermal indoor curtains, thermal mass interior walls (earth, concrete, tile, rocks). In that case, a square or dome house would be fine, so you have lots of wall space exposed to the warm afternoon sun. In my case, in the hot desert, I want to be sure that not too much of the house is exposed to the hot afternoon sun to the west, so I have a rectangle with a thin west side. The sides of my house face exactly North/South and East/West. My porches are a wonderful way to keep the sun off the walls of the house. With our dry climate, the temperature can vary greatly in the sun and in the shade.

Much can be done to cool any house with trees and vines. If you want the heat of the sun in the winter, but you don't want it in the summer, then you can find trees who drop their leaves in the winter to shade the west side of your home. Or plant gourd vines or even squash vines and remove the heavy squash. They grow very, very rapidly. Whatever works.

So, you get the idea. Figure out from your climate, where you want the sun warming your house at what time of year and where you want shade at what time of year, then use insulation, thermal mass, or shade from plants (or anything else) as you need it. Thermal mass on the inside of a house is a good idea in any climate. It helps maximize whatever cooling or heating you use. You can do this on any home. Insulate those ducts and any joints, also. I stuff towels in my cooler ducts in the winter. Hope this helps!

Keep it Simple - and be kind!
Carolyn