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CONSIDERING SOLAR HOT WATER TECHNOLOGIES
 Sighting and Orientation
 Solar hot water panels like Photovoltaic panels also need to face South, but, unlike Photovoltaics, thermal panels can tolerate some shading. 40 degrees (a 10/12 or a 12/12 pitch roof) is the optimum angle for year-round production. Domestic Hot Water (DHW) only systems (not for supplemental heat) – particularly those used seasonally more in the summer can be very effective even on a fairly flat pitched roof and varying from direct south by even 50 – 60 degrees east or west. Solar hot water panels are best mounted on the roof or close to the building.
Supplementing hot water heating with solar panels is a very effective way to help the Environment and save money as well.
- Solar Hot Water reduces your dependence on imported fuels and provides a hedge against future fuel cost increases.
- Has a good payback and then continues to save you money.
- 2 solar hot water panels will reduces carbon dioxide emissions by about 7100 lbs./year if supplementing electric water heating, 3100 lbs/year if propane, 3760 lbs/year if oil (equivalent to driving an average car over 10,000 miles).
Costs
A 2 panel solar hot water system costs $5,000-$8,000 installed depending on how complex it is to connect to your existing hot water heater. These systems are eligible for the state tax-credit; Solar tax credits at the federal level are 30% of system cost. National Grid offers a $1500 incentive for residential installations who are National Grid gas customers. $3 per avoided therm (based on the 1st year avoided therms) incentives are available for multi-family and commercial installations of National Grid customers.
System Type and Sizing Considerations
 For year-round Domestic Hot Water only systems, a good rule of thumb in New England is to plan for one 4’x 8’ flat plate collector per person in the household. This is optimum sizing for Domestic Hot Water – and will provide 60 – 80 % of your Domestic Hot Water heat fossil-free from the sun. But, keep in mind that if your budget or roof space constraints limit – say a 4 person household to a 2 or 3 panel system; it will still perform very well and offset a large portion of fuel use.
 For heating your home as well as domestic hot water, a solar thermal system can supplement heat needed for radiant heating systems; it is an ideal match because radiant floor systems use relatively low temperature warm water, and solar collectors produce lots of that in the winter. Another good home heating option for solar is a ‘hydro-air’ system; especially good for retrofitting homes with existing ducted air heating (or cooling) systems. These types of systems require more panels and a larger storage tank.
Pool and spas also interface well with flat plate collectors solar thermal systems and can help reduce the fuel costs associated with heating the water and the heat may be used to heat the home in the winter.
In order to participate in this program, you are required to have a thorough site evaluation to determine the feasibility of a solar thermal system at your location. Click here for the site survey request form, a preliminary site evaluation form, that you need to complete in order to schedule your comprehensive site analysis.
Self-Reliance works with reputable, locally-based solar installers to conduct the site evaluations and to present you with recommendations for moving forward with a system. Our solar evaluators will thoroughly assess your available south-facing, unshaded roof space, and your hot water demand so that they can propose the best system to meet your needs.
After the site assessment, our solar contractor partner will send you a written evaluation outlining the proposed system recommendations and any necessary site considerations that would be required to address prior to installation. The cost of the site analysis is $95. Our schedule for site visits fills up quickly, and rebates are available on a first come, first served basis, so please return the preliminary site evaluation sheet, along with a check made payable to Self-Reliance, promptly so that we may schedule your visit as soon as possible.
Thanks again for you interest in our program. We look forward to working with you to obtain solar energy.
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