How to save on hot water costs

By Tim Gould
Energy

Fri, May 16 2008

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Hot water, like heat, is a necessity. Over the course of one year, the average household — a home with two adults and two children — uses about 230 therms of natural gas or 3,500 kilowatt-hours of electricity to heat water. At current rates of $1.80 per therm and $.018 per kilowatt hour, this energy use converts to $414 and $630 per year, respectively. And there are other fuels available, such as propane and oil.

Of course, hot water usage varies considerably, depending on a number of factors including household size, age of inhabitants, work schedule, and water heating capacity, among others.

When it comes to conserving energy and saving money, hot water is an area in which significant savings can be realized. Water heaters use energy in three ways: demand, standby, and distribution.

Decreasing demand by reducing the volume of hot water used is fairly simple: Take shorter showers, install low flow (2.5 gallons per minute) shower heads, and use faucet aerators at sinks. These are no-cost or low-cost approaches that work. They save not only on the cost to heat water, but the cost of water itself.

Reduce standby heat loss by lowering the hot water storage temperature to a range of 120 to 126 degrees. Not only does this save energy and thus money, it also prevents accidental scalding by water that is too hot.

Distribution losses can be reduced by adding insulation around pipes. Also, an insulation blanket wrapped around an old water heating tank can save up to 10 percent of total heating costs alone. However, if your tank has 1.5 inches or more of foam insulation or the label says R-10 or more, adding a tank wrap will not help much.

When it comes time to replace your hot water heater, take your time to evaluate the best options. When they fail, people typically replace hot water heaters in a hurried fashion and don't even consider efficiency.

High efficiency water heaters generally have efficient burners, electronic pilots, and a high level of insulation. Try to get a water heater with the highest Energy Factor (EF) possible. If you have to continue heating water with electricity, consider adding a solar hot water system. If you have to replace your boiler, an indirect-fired hot water heater is more efficient than tankless coils and standalone hot water units.

Don't take your hot water for granted or ignore potential money-saving improvements. It's a necessity that usually can be made more energy efficient.

Tim Gould is director of Energy Egghead, an Amesbury-based company that can be found at www.ENERGYEGGHEAD.COM and provides professional energy audit and conservation services.