My Solar Retrofit – Solar Hot Water

(This is Part 6 of a series about the solar remodel I did on my house in 2007. Start here.)

One thing I had wanted in a home for many years was solar hot water. I’ve had solar showers for camping (and power outage emergencies!), so I was aware of the power of the sun to heat water.

I understood how it worked, but I did a lot of research anyway. I found this at www.energysavers.gov:

Solar water heaters—also called solar domestic hot water systems—can be a cost-effective way to generate hot water for your home. They can be used in any climate, and the fuel they use—sunshine—is free.

Solar water heating systems include storage tanks and solar collectors. There are two types of solar water heating systems: active, which have circulating pumps and controls, and passive, which don’t.

Most solar water heaters require a well-insulated storage tank. Solar storage tanks have an additional outlet and inlet connected to and from the collector. In two-tank systems, the solar water heater preheats water before it enters the conventional water heater. In one-tank systems, the back-up heater is combined with the solar storage in one tank.

My next step was to call installers for quotes. I first called (and ultimately hired) Valverde Energy. Larry Mapes, the owner, came out to the house, and we talked about my energy needs. My daughters were in high school and close to going to college. We decided to size the system for my future use living here alone. It could be added onto later when a family lived here again. The system would have been too large if I’d put in enough panels to cover laundry and hot shower needs for me and two teenage girls.

We installed a two-tank, active system, like the top image. The cost was about $7000. We crunched numbers and saw that it would pay for itself with energy savings in about six or seven years. I am halfway there! Actually, with tax credits, I’m probably even closer. I haven’t calculated that figure, but nevertheless, I love that the sun heats my water and that in a couple more years, my hot water will be free!

To make the most of solar hot water, it needs to be used in the middle of the day while the sun is doing its work. Later in the day, it is still effective, but not so much. I’ve already written about how to maximize your solar hot water.

My girls were home for two years before heading off to college and boarding school. Once I was home alone, my gas bill for hot water was about $15/month. I don’t make elaborate meals for myself, so that cost was mostly for hot water needs. When the girls are home on vacations, the gas bill does not go up much, since they sleep late and shower in the middle of the day or in the evening. I now have one living at home, and even with heating that room, my gas bill is not above $30. I credit this to the solar hot water AND a front loading washing machine.