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News In Numbers: In Sunny San Diego, Few Install Solar Hot Water

Photo by Chris Wilder / Solar Services of San Diego, Inc.

This undated photo shows a solar water heating system on a Jamul rooftop.

When most people think about solar energy, they think about solar photovoltaic panels that make electricity. But there are also solar water heating systems, which can be cheaper.

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Nearly 40 years after California began offering inducements to people to heat their shower water using the sun, Brad Heavner of the California Solar Energy Industries Association still has to remind them the technology even exists.

When most people think about solar energy, they think about solar photovoltaic panels that make electricity. “But there’s also solar water heating systems that are very effective at using energy from the sun,” Heavner said.

Panels that heat water are not sparkle blue. Instead, they are often a dull black inside. It’s all about absorption. And they are larger than panels for electricity.

This map shows just how few San Diego County residents are opting to install the systems, even if they are cheaper than solar electricity.

A data set obtained from the state shows fewer than 500 solar hot water systems installed since 2010. The systems vary, but here is one scenario for how they work on a single-family house:

Say you have a gas water heater. A contractor will install one or two water heating panels on the roof, plus an 80-gallon tank next to your water heater. Now the sun will preheat the water on the roof before it flows into your existing water heater. That means the gas doesn’t turn on nearly as often.

Chris Wilder is president of Solar Services of San Diego Inc., which the data indicates has installed more residential systems locally than any other company in the past six years. He said the average total cost for a house installation is $6,000 to $8,000. California rebates $1,500 to $3,000 on the cost of each system. Wilder said his own summer gas bill dropped to $5 to $12 a month when he installed his.

If instead of gas you have an electric hot water heater, the solar setup can be simpler. Your existing water heater is removed altogether, and a tank of solar hot water, assisted by an electric coil, is installed on the roof. Currently there are no rebates for people with that sort of system, so homeowners pay full cost.

Cost is no doubt one deterrent hurting sales, but Wilder, like Heavner, said many people are just unaware of the possibility. “There are more people marketing solar electricity than marketing solar hot water,” he said.

Many of the solar hot water installations in San Diego County sit on apartment buildings and condos. The data show Adroit Energy Inc. did the largest number of those installations. People may be more familiar with solar pool heating. The data set shows California Solar Thermal Inc. was the most prolific installer of those.

The state data comes from the California Solar Initiative. Building owners who installed systems but didn’t request a rebate might not show up in the data. Heavner, however, said he thinks most owners do pursue the rebate.

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