High-Efficiency Gas Water Heaters

High-efficiency gas water heaters have several features that reduce the cost of heating water. First, the tank walls have higher levels of foam insulation, as high as R-13. Secondly, instead of having a standing pilot light, a high-efficiency model utilizes an intermittent-ignition to reduce the time that the pilot light burns. The intermittent-ignition device provides a spark to ignite the pilot flame only when needed. Finally, heat exchanger efficiencies are improved, allowing heat from the gas burner to more efficiently and completely heat the water in the tank.

What To Look For

The Gas Appliance Manufacturers Association (GAMA) sponsors an efficiency certification program. This program verifies manufacturers' equipment efficiency ratings according to a standard test method. Efficiencies of water heaters are expressed by a number called an Energy Factor. A Consumers' Directory is published biannually which lists the manufacturers' model numbers and Energy Factors. Units with an Energy Factor of .60 or higher are considered energy efficient. The Federal Trade Commission (FTC) requires that all storage type water heaters be labeled with an "Energy Guide" label, which is based on the GAMA certification. This label shows, based on the national average cost of fuel, the annual operating costs of that particular water heater. The label also shows how that particular water heater compares with all other comparable models.

Insulating the Tank

To increase the efficiency of an older, existing water heater, an insulated jacket can be installed. Most water heaters have some insulation built into the tank. Unless the insulation is R-10 or more it is recommended that an insulation jacket be added when the water heater is located in an unheated area such as an unfinished basement or garage. Although the surface of the water tank may not feel warm, your tank may still be losing heat. To test, hold your hand against the side of the tank, then hold your hand against something metal in the same room, perhaps a metal shelf, a tool box, etc. Usually the other metal will feel cooler than the water heater tank. The difference is due to heat loss from the tank.

Insulating Pipes

Hot water pipes, especially with circulating systems, should also be insulated in unheated areas, using a foil-faced fiberglass insulation or foam insulation sleeves. The fiberglass can be installed in strips tied to the pipe with wire or tape every six to eight inches, foil facing out. The foam simply slips onto the pipe through a slit in the sleeve; the slit is then sealed with tape. The foam is recommended, as it is more effective and much easier to install.