Water heating is typically the second largest consumer of energy in the home, accounting for 20 percent or more of a household’s annual energy budget. You might be most familiar with cutting your hot water demand by using low-flow faucets and showerheads, as well as efficient water-using appliances. Here are some other tips that can help you reduce water-heating costs.
Mix It Right. If you find yourself turning on the cold-water tap along with your hot water to get the right temperature, your water heater temperature is probably set too high, and you’re wasting energy and money. Many water heaters are set to 140°F or higher, but for most households a temperature setting of 115°F to 120°F is sufficient. For each 10°F reduction, you can save up to 13 percent on your water heating costs. Check your water heater owner’s manual on how to adjust the thermostat on your particular model. Many thermostats do not have numbers on them, or are inaccurate, so you may have to check your water temperature with a thermometer.
Turning down the water heater temperature has additional benefits: Hotter water can cause scalding, and children and seniors are most at risk. Scalding occurs in 2 seconds at 150°F and 15 seconds at 140°F. Also, hot temperatures increase the rate of corrosion on internal fittings and other surfaces in the water heater.
Wrap It Up. A conventional tank-style water heater uses energy to maintain the temperature of the water even when no hot water is being used. This is due to “standby losses”—the heat conducted and radiated through the walls of the tank. These standby losses can represent 10 to 20 percent of a household’s annual water heating costs. Adding an insulating layer to keep the heat where it belongs is very cost effective. Installing an R-7 to R-11 insulating jacket can greatly reduce heat loss, saving 4 to 9 percent of your water heating costs. With savings like this, the insulating jacket pays for itself in less than one year. For safety’s sake, carefully follow installation instructions and leave the thermostat uncovered. On gas water heaters, isolate the jacket from the flue or the burner.
While you are at it, insulate hot water pipes wherever you can access them. This is especially critical for the first three feet of pipe that exit the water heater. Pipe insulation is a split tube of foam rubber that comes in a variety of diameters. Be sure to choose the right size so you can fully close it around the pipe. Insulating pipes reduces heat loss as hot water flows to faucets, and reduces the time it takes hot water to arrive.