This 1929 colonial-style house is typical of the houses built in Urbana-Champaign in its time. It was built with no insulation in the walls and only a thin layer of insulation in the attic and between the floors. It was originally heated by burning coal, but later switched to natural gas. At the time it was built, there was little concern about the environmental consequences of burning fossil fuels, including the threat of climate change.
The residents of this house have lived in year-round comfort for many decades, thanks in large part to the burning of coal and natural gas for household heating, hot water, and clothes drying, in addition to electricity for running the air-conditioner and the many appliances of a modern home. But there is a dark side to this comfort—carbon dioxide, a waste product of fossil fuel burning. It is generated both at the house by burning natural gas and at the electric power plant by burning coal and/or natural gas. Carbon dioxide emissions are accumulating in the atmosphere and have the potential to alter the earth's climate drastically.
Is there another way to have the same comforts without burning fossil fuels? It's already known that a solar-powered house can be built in Central Illinois at a reasonable cost (as was accomplished with Equinox House). It is more challenging to retrofit an existing home to solar power at a reasonable cost.
Here is the strategy used to convert this 1929 home into a zero net energy house, dubbed Colonial Solar House:
The energy source is solar: photovoltaic modules are used to produce electricity directly from sunlight.
Geothermal heating and cooling is used; this is the most efficient way to heat and to cool a home with electricity.
The need for heating and cooling is reduced by weatherization.
The demand for electricity is reduced by using high-efficiency appliances.
Colonial Solar House is an all-electric house. No natural gas is used, because unlike sunlight, natural gas is not a renewable resource.
All four of the steps above are necessary to make Colonial Solar House a zero net energy home. Each step on its own has its merits, however, and may be of value to your own home.
You can explore each step through the links below: