If your storage water heater doesn’t have heat traps, you can save energy by adding them to your water heating system. They can save you around $15-$30 on your water heating bill by preventing convective heat losses through the inlet and outlet pipes.
Heat traps — valves or loops of pipe — allow water to flow into the water heater tank but prevent unwanted hot-water flow out of the tank. The valves have balls inside that either float or sink into a seat, which stops convection. These specially-designed valves come in pairs and are designed differently for use in the hot or cold water line. A pair of heat traps costs around $30.
Note: If you cannot properly solder a pipe joint, heat traps require professional installation by qualified plumbing and heating contractors. Heat traps are therefore most cost-effective when installed at the same time as the water heater. Today, many new storage water heaters have factory-installed heat traps or have them available as an option.
Water Heater Insulating “Jackets”
Another cost-effective way to save on water-heating costs is to insulate your hot water heater. Unless the storage tank already has a high R-value of insulation (at least R-24), adding insulation to it can reduce standby heat losses 25-45%. (A tank that’s warm to the touch needs additional insulation.) Additional insulation will save 4-9% in water heating costs.
Insulating your storage water heater tank is fairly simple and inexpensive, and will pay for itself in about a year. You can find pre-cut jackets or blankets from $10-$20. Choose one with an insulating value of at least R-8. Some utility companies sell them at low prices, offer rebates, and even install them at low- or no-cost.
Insulating an Electric Water Heater Tank
You can probably install an insulating pre-cut jacket or blanket on your electric water heater tank yourself. Follow the directions carefully. Leave the thermostat access panel(s) uncovered. Once you have insulated the water heater, don’t set the thermostat above 130ºF. Otherwise, the wiring may overheat.
Consider placing a piece of rigid insulation (a bottom board) under the tank. This will help prevent heat loss into the floor, saving another 4-9% of water heating energy. This is best done when installing a new water heater.
Insulating a Gas Water Heater Tank
It’s best to have a qualified plumbing and heating contractor adds the insulation to gas and oil-fired water heaters. If you want to install it yourself, however, follow the directions very carefully.
* Keep the jacket or blanket away from the drain at the bottom and the flue at the top
* Make sure airflow to the burner isn’t obstructed
* Leave the thermostat uncovered
* Don’t insulate the top of a gas water heater tank. The insulation is combustible and can also interfere with the draft diverter.