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When purchasing a water heater, size and energy factor rating matter

By Sheila Yount|

The Marathon water heater’s tank is made of a tough, lightweight polyethylene outer shell that is guaranteed never to leak or rust.

Heating water is one of the biggest users of energy in your home, so it is wise to make the right choice when the time comes to replace your old water heater or buy one for a new home.

According to the U.S. Department of Energy, water heating costs make up about 14 percent of a typical single family home’s energy bill, compared with 29 percent for heating and 17 percent for cooling. The most common water heaters in the U.S. are fueled either by electricity or natural gas.

When choosing a water heater, the first decision to make is what size to buy. A 50-gallon unit is usually adequate for an average family. Next, look for the bright yellow energy rating tag and check the unit’s energy factor (EF) rating.

“Always strive to install an electric unit with the highest EF rating possible, at least a .90 (90 percent efficiency) rating,” says Bret Curry, residential energy manager for Arkansas Electric Cooperative Corporation (AECC). Natural gas water heaters are inherently less efficient energy users because a significant amount of energy escapes through the unit’s flues, although operating costs may be more or less than electric water heaters, depending on rates and fuel prices, he adds.

For those interested in electric water heaters, consider two of the most efficient ones available today — the Marathon, produced by Rheem, and the General Electric GeoSpring Hybrid.

The Marathon water heater comes with a lifetime warranty on the tank, which is made of a tough, lightweight polyethylene outer shell that is guaranteed never to leak or rust. It is insulated with Envirofoam foam insulation and has an energy factor rating of .91 to .95.

An even more efficient unit is the G.E. GeoSpring Hybrid water heater. It is Energy Star-rated with an energy factor of 2.35 or 235 percent efficiency. It uses heat pump technology to heat water. And for those thinking about replacing a heating and cooling unit, note that you can get virtually free hot water as a byproduct of a geothermal heating and cooling system.

Further cutting water heating costs

Here are other ways to save on water heating costs:
Make sure your water heater is set no higher than 120 degrees. This level will provide adequate hot water for most families.
When possible, place your electric water heater on a two-inch thick rigid insulation board to insulate the tank’s bottom.
Insulate all hot water lines above and beneath your floor. If you’re going to have a concrete slab poured, insulate hot water lines that will be located in slab before concrete is poured.
Locate your water heater in a conditioned area of your house, preferably close to the center of the house.
If you own an electric water heater with an energy factor of less than .90, consider adding an insulating blanket over the unit to further insulate it. These are available at most home improvement stores.