Savings
Heating water typically accounts for 20% of a home energy usage. The
Department of Natural Resources estimates that a properly sized solar
domestic water heater will meet 80% of a homes hot water usage. And, unlike
on-demand systems, solar water heaters heat water without using
any fossil fuel. Customers find that on average they save $35 per month per
installed
solar water heater over using an old electric water heater.
Incentives
Solar domestic water heater systems qualify for both the 50% state credit and the
30% federal credit. These systems will pay for themselves in as little as 2.5 years
How they work
In most installations we start by replacing the existing water
heater with a new tank that has an external heat exchanger. A flat plate solar collector is mounted on the roof
and copper tubing is run from the collector to the new water heater tank. A pump is installed
that is operated either by a 120 V supply or directly by a small photovoltaic panel. The
system is then filled with a highly specialized glycol solution. During the day the pump
circulates the glycol solution from the external heat exchanger on the water heater tank
up to the solar collector on the roof where it is heated by the sun. The glycol solution
then returns to the tank to heat your water. The water can be heated to 180 degrees
solely
by solar energy, but don't worry, we cut the temperature back to 120 degrees using a thermal
mixing valve. It is heating the water to a higher temperature that allows the
water to maintain its temperature over night. For prolonged periods of
inclimatic weather there is a back up heating element.
Maintenance
Changing the glycol is recommend at five year intervals.
Warranty
The tank is warranted for 6 years and the flat plate collector for 12 years.
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