Tankless heaters deliver hot water on demand
Published 9:00 pm Wednesday, October 18, 2006
Tankless water heaters, also known as “on demand” or “instantaneous” water heaters, are becoming a hot item in the United States after many years of use in Europe and Japan. American homeowners are using the remarkably small devices to fill their increasingly large jetted tubs, save space and, perhaps, cut their utility bills. In Washington, such water heaters have made their way into numerous environmentally friendly homes.
Advantages: Conventional water heaters, which hold an average of 60 gallons of water, require off-and-on heating as well as large insulated tanks to maintain a substantial hot water supply. With tankless water heaters, you heat only the water you use, which means you should never “run out” of hot water. Most units are about 2 feet tall, 18 inches wide and 6 inches deep and can be installed in small spaces, such as a bedroom closet or on the outside of your house for easy venting. Most tankless heaters have a life expectancy of about 20 years, compared to 10 to 15 years for conventional models.
Limitations: If you don’t buy a heater equipped to deliver enough BTUs (units of heat) for your demands, you might not be able to provide enough hot water to your home. Gas-fired tankless water heaters produce higher flow rates than electric ones. Wiring in most homes generally will not support a tankless electric water heater with large enough capacity to serve an entire home. Tankless water heaters can also increase the amount of time it takes for water to run hot after you turn on the faucet.
How it works: When you turn your hot-water faucet on, water enters a heat exchanger. Then a sensor detects water flow and a burner is automatically ignited. Water circulates through the coil-like exchanger and is heated instantly until you shut off the faucet.
Cost: Tankless water heaters start at about $600 for basic models. High-end units cost $3,000 or more. Conventional water heaters, meanwhile, typically cost $300 to $1,000. Energy savings estimates vary widely, but according to the U.S. Department of Energy, homes that use 41 gallons or fewer of hot water daily, tankless heaters can be 24 percent to 34 percent more energy efficient than those using conventional tank heaters. In the end, it will depend on your usage and the type of tankless water heater you buy.
Select energy-efficient water heaters, including some tankless models, can earn you $300 to $500 in tax credit. See www.energystar.gov for details. Tankless heaters with a constantly burning pilot light can waste energy because the gas is not being used to heat water. You might consider a model with a spark-ignition device similar to those used on kitchen ranges.
Where to buy: Local water heater companies and home improvement stores sell a variety of tankless water heater systems.
Study up: Learn more at www.eere.energy.gov and www.aceee.org. Popular brand sites include www.rinnai.us, www.boschusa.com and www.takagi.com. Read opinions on tankless heaters at www.askthebuilder.com and www.epinions.com.
Sources: American Council for an Energy Efficient Economy, U.S. Department of Energy, Los Angeles Times-Washington Post News Service, U.S Department of Energy
Learn more
Washington Energy Services of Seattle (206-378-6655) will have a tankless water heater on display at the Everett Fall Home Show.
Many other heating, cooling and energy-service vendors at the show also sell tankless water heaters, including:
Snohomish Energy Services of Snohomish (360-563-9199)
CM Heating of Arlington (425-259-6666)
Home Town Heating &Stove Shop of Marysville (360-659-6901)
Sundance Energy Services of Renton (425-481-9660)
