February 10, 2017

Solar Hot Water: The Other Solar

Leslie Nash, Project Administrator

When you hear the word “solar,” what do you picture?  Nowadays, most Massachusetts residents picture solar photovoltaic (PV) panels due to the amazing growth of solar PV in our state.  There is also another kind of solar energy for homes and businesses to consider: solar hot water (SHW), also known as solar thermal.  A SHW system looks similar to a solar PV system from the outside, but while a solar PV system converts the sun’s energy to electricity, SHW systems capture the sun’s energy to create heat that can be used to heat hot water or even supplement a home’s space heating system.

Green-thinking homeowners can install both solar PV and SHW collectors to maximize their use of the sun’s energy.

Some homeowners opt just for SHW, which can be a great energy solution in situations where the roof is too small for a PV system or does not face south. Typically, a home would only need 2 to 3 SHW collectors to provide up to 80 percent of its hot water needs, so there is less demand for roof space.  SHW installers may also be able tilt or mount the collectors on an angle, rather than laying them flat, which is what allowed Quinton Zondervan of Cambridge, MA to install SHW. 

John Moore from New England Solar Hot Water described Quinton’s situation: “Quinton had already covered his west-facing roof in PV.  His east-facing roof is shaded and not ideal for a solar installation, so we presented him with the idea of an awning-mount installation on his south-facing wall.”

Quinton is an example of a homeowner who wants to be 100 percent renewable.  He uses the electricity from his PV system to charge his electric car and plans to install an air-source heat pump soon.  He is also president of a local non-profit, Green Cambridge, which works on sustainability issues throughout the city.  Quinton loves his SHW system; he says the water is very hot and his natural gas bill is down to almost zero in the summer, except for his gas stove.  

There are strong incentives available to Massachusetts residents who want to install either solar PV or SHW (or both!) on their home.  As you’re looking to save costs and reduce your greenhouse gas emissions, consider solar hot water.

“I think the most interesting part of our work is meeting with the variety of people interested in solar hot water,” said Moore. “We have installed systems on multi-million dollar mansions owned by high-tech executives as well as tiny moderate cottages housing retired couples.  They vary greatly, but all share one interest: taking advantage of free energy from the sun!”

Visit MassCEC’s SHW webpage for more information about the technology, our rebate program, and finding an installer.