Sungevity of California will do an estimate for the cost of adding solar energy to your home without one of their employees coming to your house. Sungevity’s software application essentially eliminates the money and time it takes an installer to visit your house, take measurements and prepare the estimate.
Sungevity’s website provides a box for your address and without even seeing your residence gives you a quote for adding solar energy to your house. Within 24 hours your quote arrives, including the savings over 25 years.
Their software application uses Microsoft Virtual Earth which gives data from different angles, letting Sungevity calculate pitch. The data provides a fairly accurate estimate.
Currently Sungevity only operates in California, but plans to operate in other states. They are looking at either employing subcontractors or selling their estimator service.
http://www.Solar-Estimate.org provides free online solar estimating tools as well. It’s a free public service and provides a lot more detail and options that Sungevity’s site.