A solar water heater is an investment that's great for the environment – and your energy bills.
How it works
Solar water heaters use thermal panels to collect heat from the sun's rays. These panels, which require an unshaded south-facing location, are usually installed on a rooftop.
Sunlight passes through the panels and is collected by a dark absorber plate. The plate warms liquid passing through pipes - either the home water itself, or a heat-transfer fluid like an environmentally safe antifreeze.
If an antifreeze mixture is used, the heat is extracted from the fluid through a heat exchanger inside the water heater, just like a standard natural gas or electric model.
According to the U.S. Department of Energy, solar water heaters can operate in any climate. In fact, the colder the water, the more efficiently the system works. But keep in mind that most local building codes require a conventional water heater as a backup in case of emergencies.
The sizing and installation of a solar water heater is a professional job - your contractor will use worksheets or computer programs to determine the right size for your family's need, as well as the best place to install the panels.
The initial cost of a solar water heating system ranges from $1,500 to $3,000; in many cases, the cost can be paid back in energy savings in less than eight years.
If you currently have an electric water heater, switching to a solar model is a good investment - some homeowners have cut their electric bills by 50 to even 80 percent. The energy savings can pay back the price difference in about four to eight years.
Replacing a natural gas water heater with a solar system won't offer such dramatic savings, because gas models are already more energy-efficient than electric.
If environmental impact is an important consideration, a solar water heater can make a difference. If you replace an electric water heater with a solar system, more than 50 tons of carbon dioxide emissions will be displaced over the 20-year lifespan of the equipment.