Dip Into Solar Water Heaters

Solar water heaters are the most efficient way to harness the sun's power to reduce your home's carbon emissions.

| January/February 2010

  • Apricus Solar provided solar-thermal panels for the Cranberry Ridge LEED Platinum home in Freeport, Maine.
    Photo Courtesy Apricus
  • Heliodyne determines which type of system is best for a given home based on location, number of household members, water quality and more.
    Photo Courtesy Heliodyne
  • Apricus Solar provided solar-thermal panels for the Cranberry Ridge LEED Platinum home in Freeport, Maine.

More than 100 years ago, William J. Bailey patented the first solar water heater, the Day and Night. Relatively affordable and reliable, the heaters were a lot more efficient than cooking a big pot of water on the woodstove. In the United States, solar water heaters were eventually eclipsed by gas and electric water heaters, but in other countries solar water heating technology, also called solar thermal, thrived. Now seeing a U.S. resurgence, solar thermal is one of the simplest and most-efficient means of saving energy, says John Perlin, co-author of A Golden Thread: 2,500 Years of Solar Architecture and Technology (Cheshire Books, 1980).

System specifics for solar water heaters

Solar water heaters can use either a closed-loop or an open-loop system. In a closed-loop system, rooftop solar collectors heat a nontoxic antifreeze mixture. Once heated, the mixture is pumped to a heat exchanger—or solar tank—through copper tubing, where it heats cold water for use. An open-loop system works similarly but uses water instead of the antifreeze mixture.

Closed-loop systems use less energy and are better suited for houses in which the building configuration requires pipes to be laid flat. It’s crucial that a closed-loop system be appropriately sized for the household—a too-large system results in unused fluid that can damage the system’s mechanics. Open-loop systems heat efficiently and don’t need to be sized as specifically as closed-loop systems, but they require a drainback tank and use more energy moving fluid.

Types of solar water heaters

There are essentially two types of heaters: a flat plate collector and an evacuated tube. “The evacuated tube is generally more expensive,” says Ryan Mayfield, president of Renewable Energy Associates in Corvallis, Oregon, “but depending on where you live, it can really have benefits. Evacuated tubes perform really well in cold, clear climates, like the Rocky Mountain region.”

Evacuated tube systems are complex, Mayfield says. If one of its 20 to 30 tubes breaks, the system must be replaced. “It’s not something you can fix,” he says.

Flat plate collectors are very simple and very robust. However, they lose heat more readily than the evacuated tubes.

Installing a solar thermal system requires plumbing skills and the ability to work with copper. Professional installation takes about two to three days and costs approximately $6,000 to $9,000 for an average residential system, depending on your region and available rebates or tax credits.

Which Solar Hot Water System is Right for You?

Closed-loop systemPros: Good freeze protection; requires less energy to move fluid; pipes can be laid horizontally (if you’re working with rafters)
Cons: Sizing is critical; unused fluid gets stuck in the collector and changes chemically, which can damage the mechanics

Subscribe today and save 58%

Subscribe to Mother Earth Living !

Mother Earth LivingWelcome to Mother Earth Living, the authority on green lifestyle and design. Each issue of Mother Earth Living features advice to create naturally healthy and nontoxic homes for yourself and your loved ones. With Mother Earth Living by your side, you’ll discover all the best and latest information you want on choosing natural remedies and practicing preventive medicine; cooking with a nutritious and whole-food focus; creating a nontoxic home; and gardening for food, wellness and enjoyment. Subscribe to Mother Earth Living today to get inspired on the art of living wisely and living well.

Save Money & a Few Trees!

Pay now with a credit card and take advantage of our earth-friendly automatic renewal savings plan. You’ll save an additional $5 and get six issues of Mother Earth Living for just $19.95! (Offer valid only in the U.S.)

Or, choose Bill Me and pay just $24.95.

Facebook Pinterest Instagram YouTube Twitter

Free Product Information Classifieds

click me