Software as a service has come to solar.

Next year, Sungevity will let other solar installers use its project estimator for a fee, said president Danny Kennedy. The company has created a system that takes satellite data and a person's average utility bill to come up with an estimate for a solar system. The software takes into account a variety of factors including the pitch of the roof and azimuth, or relation to the sun, of the home.

In all, the software can cut the cost of a solar install by 5 percent to 10 percent or more because installers don't have to clamber up on people's homes to perform an estimate. It takes the company only a few hours to concoct an estimate that includes how long it will take to pay for itself.

Sungevity will license its system to installers outside of California. It will initially target seven other states and also look to expand overseas. RoofRay has a similar online solar estimator. Kennedy added that Sungevity, which started installing solar systems this year in the state, is already facing a backlog. (Kennedy made the announcement at the End-to-End Electricity conference in New York sponsored by Greentech Media.)

Cutting the cost of solar installs has gained more focus in the past two years. Although companies and researchers have poured millions into increasing the efficiency of solar cells, comparatively little has been sunk into the construction project that is an install. Installation, however, comes to around one-half to one-third of the total cost of system.

Among other tricks to reduce installation costs include: integrating the module with the frame at the factory, standardized components, building integrated photovoltaics and using software to organize installations to cut down on the number of installers needed.