Solar Hot Water Heating Systems for Your Home

With the proper panels, collectors, and system type, a solar hot water heater will benefit the planet and your wallet.


| August/September 2016



Solar Map

The National Renewable Energy Laboratory rates the majority of the United States as “Very Good” or “Excellent” for modern solar thermal technology.


Chart courtesy The National Renewable Energy Labratory

Solar thermal systems have been the water-heating method of choice for homes near the equator for decades — back when many North Americans relied on a woodburning stove and kettle! Spared the threat of freezing, “batch” equatorial systems are simple, cheap, and effective. North Americans also have a long history with solar hot water, but wintertime freezes — found in much of the United States and Canada — forced the development of freeze-ready “flat-plate” collectors, which went mainstream in California and Florida in the 1970s. Today, the innovative solar thermal industry produces highly efficient models capable of heating water as far north as the Arctic Circle! As a solar water heating system installer, I’ve met hundreds of people who’ve turned to solar water heating as a way to save money and to reduce their carbon footprint.

The solar thermal systems that I promote provide a return on investment between 5 and 15 percent, depending on the type of fuel you’re replacing, your location, and which state utility incentives are available. A residential solar water heater will offset greenhouse gas emissions by three-quarters of a ton of carbon dioxide every year — the equivalent of an average driver cutting 1,300 miles from their annual commute. Moreover, solar water heaters qualify for the 30 percent federal tax credit until 2020, so the time to install is now!

If your plumbing and wiring skills are up to snuff — and code — you’ll have no trouble assembling a solar water heater for your home. For everyone else, a commercially available system is the best recourse. This article will present four initial steps to take and the general options to consider when shopping for solar thermal systems.

Step 1: Reduce Hot Water Consumption

Your first step toward hot water self-sufficiency is to reduce waste. Address your household’s water-wasting habits. Shut off the hot water when shaving, soaping up, and rinsing the dishes; better yet, embrace the thrill of a cold shower! Insulate as many hot water pipes in your home as possible. Mineral wool and fiberglass insulation are ideal for high-heat applications, such as indoor solar piping, and polyethylene is recommended for temperatures up to 180 degrees Fahrenheit. Finally, choose high-efficiency washing machines and dishwashers, and low-flow showerheads and faucet aerators to reduce demand.

Step 2: Choose a Solar Water Heating System Size and Site

After reducing waste and determining your hot water needs, you’ll need to size the best system for your household and your wallet. Solar water heaters rarely provide 100 percent of household hot-water needs — there are just too many cloudy days during the year, especially at my home in Wisconsin. Instead, solar thermal systems typically provide 50 to 75 percent of your annual load depending on location and season. Check with a local solar specialist about what to expect in your area.

Whichever capacity you choose, you’ll need a separate solar storage tank and backup water heater — the same tank can’t do both jobs efficiently. Collectors are typically mounted on a roof, but you can also mount them on the ground near a dwelling. Wherever you choose to site them, remember that collector boxes are highly vulnerable to wind — make sure they’re securely braced and fastened!

sundug
8/12/2016 9:54:11 AM

Here's my self installed PV pumped SHW system, cost $1100, working fine for 36 years now, just replaced an expansion tank and changed fluid twice. http://www.builditsolar.com/Projects/WaterHeating/DougsSolarWater.htm#Dougs






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