How to Heat Water With Solar Power

Heating water is one of the simplest and most effective uses of solar power. Solar water heaters can greatly reduce energy costs while simultaneously helping the environment. Professional installers can provide expert advice on using a solar panel to heat water in your home, but models are also available for experienced do-it-yourselfers to install themselves. Doing the job requires a few careful steps.

Things You’ll Need:
Solar water heater tank
Solar panel
Solar panel mounts
Solar panel rails
Copper connection tubing
Compression unions
Coaxial fitting for the water heater
2 roof boots
Roof boot flashing
Drill
Hammer
Caulking gun
Caulk
Teflon tape


Perform an audit on your home to determine your heat needs. Your water company may be able to provide information on usage, though a 30-gallon capacity per person in your household is a good round figure.

Determine the size of the solar power panel you will need and whether it will fit comfortably on your roof. Generally speaking, you'll need around 20 square feet for each of the first two residents. For every additional person, add 8 square feet if you live in a sunny area or 12 to 14 square feet if you live in a cold climate.

Determine the best placement for your solar panel on your roof. You will want a location where the mountings can be secured to the rafters (a hammer can be used to "sound out" the rafters), and also one that will allow you to run pipe to your hot water heater conveniently.

Measure the precise points where the mountings should go, making sure that they line up to the positions on the panel precisely.

Install the mountings using a power drill, with screws and brackets to hold them in place. The exact type of screw used will depend on the model of solar panel.

Seal the holes with caulk or similar sealant.

Install the rails onto the mounts and fix them in place, as described in their instruction manual (exact methods vary from model to model).

Install the solar panel on the rails, making sure they are secure against wind or bad weather.

Install a roof boot to provide an opening for the connection between the panel and the water tank. This should go approximately 2 inches from the feed connection on your solar panel, and should not be placed over any rafters.

Add flashing to the boot to make the surrounding hole watertight. Use caulk for a further sealant if necessary.

Install a second roof boot in the same manner approximately 2 inches from the absorber outlet of your solar panel.

Attach the compression unions to the roof boots.

Connect the compression unions to the appropriate feeds on the solar panel using copper tubing.

Make sure all connections are tight and will not leak water.

Run copper tubing from both feeds down through the attic to the water heater.

Turn off the gas on your water heater and drain it of all water.

Install the coaxial fitting onto the water heater (exact details vary by model).

Connect the copper tubes to the fitting, making sure that the feed line (cool water out to the solar panel, which will heat it) and the return line (hot water in from the solar panel) are connected to their proper locations.

Double check all connections to make sure there is no leaking. Use sealant or Teflon tape if necessary.

Refill the heater with water and turn the gas back on.

Make sure that your solar panel doesn't violate any existing building codes in your area, and check with your water company before attempting to adjust an existing hot water heater.

Take care when working on your rooftop. Make sure your footing is solid and always have a friend or family member close by in case of an accident.