Insulation Blanket

Swaddle your water heater in a cozy insulation blanket to keep the heat from dissipating in a cold basement or closet. Usually made of plastic with fiberglass insulation, the blanket wraps around the heater and is taped or strapped on. (Make sure it doesn’t cover the top of the heater or the door that opens to the pilot light.) It takes less than 30 minutes to install and costs $5.

Foam Pipe Insulation

If your heater’s hot-water pipe travels a long way through an unheated part of the house, such as a cellar or a garage wall, the water it’s carrying can lose a significant amount of heat before reaching your bathroom (hence those lukewarm showers). Energy Star’s Doug Anderson suggests covering the first 5 to 10 feet of the pipe coming out of the heater with foam pipe insulation, which fits over the pipe like a sleeve — “an inexpensive fix that goes a long way.” It takes less than 10 minutes to wrap the pipe and costs about $3 for four three-foot tubes (check the diameter of your pipe before you shop).