How to Install a Solar-Powered Water Heater

In this video, This Old House plumbing and heating expert Richard Trethewey and plumbing and heating contractor Bob Dudley install a solar-powered water heater.

Steps:

1. Run insulated supply and return lines down to the basement.

2. Turn off the gas line to the old water heater.

3. Drain the water from the old water heater, then cut and remove the heater.

4. Use a roofing spade to remove shingles from roof.

5. Temporarily set the solar collectors into place on the roof.

6. Use a reciprocating saw to cut three holes in roof: one for the anti-freeze supply lines coming up from the basement, one for connecting together the two solar collectors, and one hole for the anti-freeze return lines going back down to the basement.

7. Fasten the solar collectors by screwing down through the flanges and into the roof rafters.

8. Mount a temperature sensor to the side of the solar collector.

9. Connect the anti-freeze supply line to the inlet side of the first solar collector; tighten the compression fitting with a wrench.

10. Install a short supply line between the two solar collectors.

11. Now connect the anti-freeze return line to the outlet side of the second collector.

12. Install flashing around each collector, then nail down new roof shingles.

13. From inside the basement, connect the anti-freeze lines to a pumping station, then continue the lines to a new water heater.

14. Connect the copper water-supply pipes to the water heater, using a tempering valve to prevent extremely hot water from being delivered to the faucets throughout the house.

15. Run a gas backup line to the water heater, which will heat water when the sun isn’t shining.