— Solar Heated Household Water

The collector

In Arizona it seemed that the sun could heat the water we needed to be hot. The local power company (SRP), the state, and the federal government all offered incentives to do this. When our “normal’ hot water heater developed a leak in 2006, we thought we would give it a try. The professional installation cost for a solar hot water system was on the order of $4500 with about $3500 returned to us in the form of power company, state and federal tax credits. So our out of pocket expenses were on the order of $1000.  A little higher than a standard hot water heater, but it seemed green.

The collector on the porch roof measures approximately 3.5 feet by 10 feet. It circulates a fluid that heats in the sun and goes down to the hot water heater and exchanges its heat with the water.

Roof temperature
Hot water tank

Conservative Energy Systems in Mesa installed our unit. They obviously have a lot of experience in installing these types of systems, and supplied us with the paperwork necessary to get energy company rebate, and state and federal tax credits. The photo on the left shows the controller in the mode where the roof temperature is displayed. Also possible is to display the water temperature in the tank. The other photo shows the heater from a distance and any outgoing connections.
Here are a couple photos – the first where the connections come thru our tile roof. The second shows the insulation around the copper delivery tubes. There are some gaps in the coverage provided by Conservative Energy Systems. Also, the Arizona sun will probably destroy such exposed rubber in 3 or 4 years, so we need to plan on replacing it.

Collector pipes enter the roof
Collector pipe insulation

To be honest, I am not convinced that the $4500 was well spent in terms of saving energy in the long term. Here is the way I see it. Prior to the installation we had already installed a $50 timer on our water heater so it would heat the water at 530am for a couple of hours. This is the time when we normally shower. The dishwasher uses hot water, too but has a heating element to help it out. Our laundry washing machine normally uses cold water, thought we sometimes use hot on whites.When the solar hot water heating system was installed, the timer was obsoleted so the sunlight during the day would heat up the water. However, after spending $4500, we still take showers in the morning and only occasionally use hot water for laundry. So even though the rebates, etc, lowered the cost, we now have an expensive system that probably doesn’t reduce expenses much compared to the timer. In fact, Arizona previously went thru a decade where solar hot water heaters were installed with subsidies, and after their lifetime and they started leaking, they were replaced with simpler, conventional heating systems.

So my advice is, if you shower in the morning before going to work, simply install a timer and have the hot water when you need it. If you have visiting family flying in some afternoon, turn it on before going to the airport and they can have a hot shower, and you will not complicate your life.

Next: Solar Heated Pool Water