The Passive Solar Home

Solar Home Chronicles 2

Tuesday, 11 September 2007

When we think about `solar homes’, many people think of buildings that are space-age and ultra-modern. Well, these assumptions are partly correct. Solar homes are new-age, since there are lots of new technologies that can be incorporated into them. They are also often modern looking, since they are a relatively new type of building. Often, people who build solar homes are of the income bracket that takes pride in building something that looks a little different.

But our understanding of passive solar homes is that they don’t have to look space-age or ultra-modern. Given the basics of their design, we think that they can look very much like the homes that you and I already live in, and they should function that way, as much as possible, too. They should also be cost-effective to build.
Solar Nova Scotia has been developing its solar shelter design over the past twenty or so years. Coming out of the `hippy’ era of granola and back-to-the-land, this organization has now come of age, with practice built on experience that makes good sense for our Maritime climate. Don Roscoe is an architectural designer who has designed dozens of solar homes for many different building sites. When he is not designing, he is the builder of most of the homes that he designs.

You have probably heard of the terms “active solar” and “passive solar”. Active solar refers to the use of some sort of technology (collector) that takes the heat from the sun and then circulates it into the building for either space heating or hot water heating, or converts the sun’s energy into electricity via photovoltaic cells. Passive solar refers to the ability of a building to collect heat from the sun’s rays without doing anything but sitting there. This is accomplished by appropriate windows and building design.

The `simple genius’ of our solar home will be its passive solar characteristics.
To familiarize ourselves with how others are designing and building solar homes, we have visited 5 passive solar homes in Nova Scotia and one in New Brunswick. They are all regular-looking family homes that share the following qualities: they are oriented so that most of their windows face south; they have a particular percentage of window glass per area of floors; they have concrete main floors to collect the solar heat; and they have some sort of circulation system that distributes this collected heat throughout the house. In each of these homes, the circulation system that distributes the heat in the winter, also distributes cool air in the summer, so these houses tend to stay within a limited temperature range, summer and winter.

Solar Nova Scotia has perfected a method of building a concrete slab, that has air ducts radiating through it from a central point, as its collection and distribution system for solar heat. During the winter, the sun will shine on this concrete floor, and the air ducts will allow the heat to be circulated from the floor into the rest of the house.

How to select a lot, to make the best use of this design, will be the topic of my next instalment.