Saving Energy: Water Heating

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.

The heat from the sun is used to warm a liquid that circulates through pipes connecting the panels to the water heater. The liquid can be 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.

Learn more about solar energy

Solar panels

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.

Installation

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 cost and benefits

The cost of a solar water heating system ranges from $1,500 to $3,000 - significantly more than a traditional tank water heater.

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collection tank

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, the electricity displaced over the 20-year life of the equipment represents more than 50 tons of carbon dioxide emissions alone.

Water
storage tank

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Are you an Alliant Energy customer?

If you’re an Alliant Energy utility customer in Iowa, Minnesota or Wisconsin, you can earn cash back when you purchase a new high-efficiency water heater.

Looking for an energy-smart plumbing contractor or retailer?

Try Alliant Energy’s online Dealer Locator to find water-heating experts in your area.

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Brochures and fact sheets:

PowerHouse: Heating Your Water
By Alliant Energy [PDF format]

Energy-Efficient Water Heating Fact Sheet
By the U.S. Department of Energy [PDF format]

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Learn more:

Solar Water Heating
Fact sheet from the U.S. Department of Energy

Water Heaters & Energy Conservation
By Home Energy Magazine

Selecting a New Water Heater
Fact sheet from the U.S. Department of Energy

Top-Rated Water Heaters
By the American Council for an Energy-Efficient Economy