If you've ever stepped into a century-old house in summer, chances are you noticed it wasn't swelteringly hot despite a lack of air conditioning. Credit goes to its design: A wrap-around porch or a big overhang keeps glaring sun at bay instead of streaming indoors. Maybe a huge oak or maple provides shade in a key location. Ample windows placed strategically can be opened and provide welcome breeze, thanks to cross-ventilation. White paint - or some other light shade reflects the
sun's heat.
You can apply "passive cooling" or "passive heating" principles to your abode, too, even if it's a modern building. It'll pay dividends. According to the U.S. Department of Energy, passive solar design can cut heating bills by as much as 50 percent.
Considerations:
Solar systems should be employed only after extensive conservation strategies have been implemented.
1. Cost - Solar energy systems typically have a high initial cost and extremely low operating costs. To reduce the high initial costs, reduce the size of the required system by the load that the solar system will need to provide.
2. Drafts - In space heating and cooling applications, the home should be weatherized and insulated to very high standards. In water heating applications, hot water piping should be insulated and water conserving fixtures should be used.
3. Sizing - The system should be sized to reflect seasonal variations in demand and in the sun's heating characteristics.
4. Combine Systems - By combining systems to perform multiple functions (i.e. space heating and water heating), the solar system investment can provide a return all year.
The goal of your solar system should be to accomplish 100% of the home's heating, cooling, or water
heating needs.
When calculating the number of panels you need, do so using winter sunshine hours rather than summer hours - there are roughly twice as many hours sunshine in summer and the wrong calculation could leave you needing to use backup power in winter more often than you would like.