Does solar power make sense for my building?

The first question should always be whether your building is energy efficient.  Energy efficiency upgrades should always precede or accompany solar investments. Next, do a solar spot check on your own.  Is your roof shaded by trees or other buildings?  If your roof is sloped, is there a south-facing slope?  If there is an uninterrupted southern exposure, your home or building may be ideal for solar PV and/or solar hot water.  Even if you have some shading, solar hot water may still work well because solar thermal collectors absorb diffuse, rather than direct, solar radiation. If your building passes the spot check, then take your investigation to the next level by visiting the National Renewable Energy Laboratory’s In My Backyard Solar Mapping Tool at www.nrel.gov/eis/imby to determine your building’s potential system size and estimated production.  Visit www. dsireusa.org for an up-to-date, detailed description of incentives available by state, and browse a list of solar installers in your area at www.nabcep.org/installer-locator or www.findsolar.com . How many solar panels are needed to provide power or hot water for an average home? For a Midwest example, the average residential home in Commonwealth Edison’s service territory in the Chicago metropolitan area uses approximately 720 kWh of electricity per month.  A 3.5 KW PV system would offset more than half of the average household’s electricity consumption.  This size solar system would require about eighteen 200- Watt PV panels.  Looking at the same household’s hot water use, a family of four would use about 80 gallons of hot water every day, on average.  In the Midwest, a good rule of thumb is that 1 square foot of solar thermal collectors is needed for every gallon of hot water consumed per day.  So, supplying 100 % of the daily hot water needs of an average family of four would require an 80 square foot system, or four typical 4 x 6-½ foot panels.

by elpc.org