Q: Replacing my older water heater isn’t in the budget right now. What can be done to make it run efficiently?
—David Tichy, Fairfield, Conn.
Lance Marques, HVAC contractor, Swezey Fuel Co., replies: There are several easy and inexpensive ways to increase a water heater’s operating efficiency and longevity. Some things—adding insulation and setting the temperature—have to be done only once. Others, such as flushing the tank and checking the anode rod, should be done annually.
The benefits of caring for your water heater are clear. Adding insulation reduces heat loss by up to 45 percent and can shave as much as 9 percent off water-heating costs. Flushing sediment from the tank improves efficiency and longevity. And making sure a viable anode rod hangs in the tank will help prevent its inside from rusting out. A used-up rod is far cheaper to replace than a new heater.
Just follow these hot water heater maintenance tips to make your hot water less expensive.
Pictured: This rusty wire is all that remains of what was once a ¾-inch anode rod made of aluminum or magnesium. Without the rod, hot water rapidly corrodes the inside of the tank, shortening its life.
Steps on How to Maintain a Hot Water Heater
1. Test the TPR Valve
- Shut off the power and the cold-water supply valve.
- Place a bucket under the pipe connected to the temperature-pressure-release (TPR) valve on the top or side of the tank. (This valve opens if the tank pressure gets too high.)
- Lift the valve’s tab to let some water out, then let go. If water keeps flowing, drain the tank partway, unscrew the old valve with a pipe wrench, and install a new one.
2. Check the Anode Rod
- Put a hose to the tank’s drain cock and let out a few gallons of water.
- Now fit a 1 1/16-inch socket onto the rod’s hex head on top of the heater (or under its top plate) and unscrew the rod. If it’s less than ½ inch thick or coated with calcium, buy a new one, wrap its threads with Teflon tape, put it back in the tank, and tighten securely. Use this segmented rod if headroom above the tank is limited.
3. Drain the Tank and Wash Out Sediment
- Drain the remaining water in the tank into the bucket, then stir up the sediment on the tank’s bottom by briefly opening the cold-water supply valve. Drain and repeat until clean water comes out of the hose.
- Close the drain cock, refill the tank, and turn its power back on.
4. Adjust the Temperature
- Find the temperature dial on the side of the tank and unscrew its cover. Adjust the dial to 120 degrees using a flathead screwdriver. For every 10 degrees the temperature is lowered, you can expect to save up to 5 percent in energy costs.
- Turn the water heater off or the thermostat down to its lowest setting if you plan to be away from home for more than three days.
5. Insulate the Pipes
- Buy some self-sticking 3/8-inch-thick foam pipe insulation that matches the pipes’ diameter.
- Slide the foam over the hot-and cold-water pipes as far as you can reach. Insulating the cold-water pipe prevents condensation in summer.
- Peel the tape and squeeze the insulation closed. If the pipe is 6 inches or less from the flue, cover it with 1-inch-thick unfaced fiberglass pipe wrap.
6. Insulate the Heater
- Cut the insulating blanket (shown: R-4.5 foil-covered bubble wrap) to fit around pipes, the TPR valve, and the temperature control sticking out of the tank.
- Wrap the side of the tank, and seal cuts with foil tape. Do not cover the tops of oil or gas heaters.
- Cap an electric heater with an oversize circle of insulation, and tape its edge securely to the side of the tank.
Tools & Materials
Looking for more help with repairs around your home? A home warranty may help. Check out the This Old Houses Reviews Team’s in-depth reviews on: