Before you install a solar system on your home, consider some of the variables listed below.

Electricity Usage

• Determine how much electricity you are using by checking your electricity bill for the past year.  A 12-month total will be most helpful, as your usage will vary from season to season.
• If you are thinking of expanding your home, adding a pool or buying an electric car, your future electricity requirements may grow.  Consult with your installer about the prospect of expanding your PV system later if necessary.

Location and Roofing

• If you have partial shade, or shade at certain times of the day, on your roof where you wish to put your solar panels, the amount of power that can be generated throughout the year will be less than is generated by solar panels that are in continuous sunlight.
• The direction your system faces makes a difference in performance. Solar panels facing south are considered ideal for generating power. Solar panels facing west and east are less ideal, and panels should never face north.  Performance may be lowered by a split system facing multiple directions. 
• Your roof needs to be in good condition to hold the solar installation. Most solar installations have a lifetime of 20-30 years.  If your roof is due for replacement in the next few years, you should consider replacing it before you install a solar system to avoid the cost of removing and reinstalling the system later when you replace the roof.

Cost

• As with any major home improvement, solicit multiple bids; SVP recommends at least three.  Quotes should include all expenses associated with the project and itemization should show:
  • Performance of system - What will be the actual power generated for use in the home? This is determined by the size of the system, the direction(s) it faces, and how much sun it receives.
  • Payback estimate - At current incentive levels (federal tax credits) and your savings on electricity costs, a payback period of between 5 and 8 years can be expected for an average system to repay your net out-of-pocket expense for installation.
• Question any discrepancies you might find between estimates.  The average total cost of systems installed in 2010 was about $7-8 per watt before rebates. 
• Because electricity rates for SVP customers are far lower than neighboring communities, be sure your installer knows:
  • How much you pay for electricity (your “rate”)
  • What your estimated savings from federal tax credits might be
  • How long it will take for your system to repay you for the cost of installation. The equation is based on your usage, how large your system will be and how much power it will actually generate, how much it will cost to install, and what the projected savings will be.

Quality Assurance

• Verify your installer is a licensed solar contractor at http://www.cslb.ca.gov. 
• Check references.
• The warranties must guarantee their work, their subcontractors’ work, as well as all the equipment provided.

More information on home solar installations is available at: http://www.GoSolarCalifornia.org.