I made it up to San Francisco for the first annual SolarDay. Held on the sunniest day of the year, SolarDay 2009 offered a showcase of solar installations including both photovoltaic and hot water technologies. 

The recession has been tough on the solar industry as rising debt-to-income ratios and ever-tightening credit markets have made it next to impossible for homeowners to finance solar installations, even though in some cases the loans can be paid back in their entirety just through energy savings.

So it's not surprising to see hot water solar making a comeback. The less glamorous (and less expensive) cousin of the solar PV panel, hot water solar panels have been around for decades and they took center stage at this year's SolarDay. 

The day featured a tour of six hot water solar installations around the city of San Francisco like the "total solar" home of Joe Cassidy pictured above (PDF) which uses solar PV panels to provide electricity and solar hot water panels to heat the home (using a radiant floor system).

The city of San Francisco currently has over 1300 solar systems installed with a total of a 7.5 megawatt capacity, and the city has set the ambitious goal of getting to 10,000 installations by the end of next year.  SF Environment offers a cool map of the city's solar installs:

 

Hot water heating alone accounts for close to 10 percent of total residential energy use, and these fuel costs can be offset by 40 percent or more through the installation of solar hot water panels. Check out SF Environment's solar hot water basics tip sheet (PDF).

In conjunction with the event, a new SolarDay website was launched which will eventually offer a state-by-state guide to going solar including costs and tax benefits. The site is running a contest now for a three-night stay at the eco-friendly Gaia Hotel & Spa in Napa Valley wine country.  

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