Intermatic WH40

Water Heater Timers


With soaring electric bills, particularly in the hot summer months, homeowners are on the lookout for simple ways to save electricity. Water heater timers allow you to control when an electric water heater turns on and off in order to take advantage of off-peak hours and savings. For residents living in areas with time-of-use charges for electricity, installing a water heater can result in significant savings.

Off-peak electricity is lower-priced electricity. Energy usage peaks during the day and evening when air conditioners and other appliances are most often in use. Off-peak hours occur at night. Installing a water heater timer that allows you to run your heater at nighttime during off-peak hours can reduce your annual electric bill.

Residential dwellings, commercial, industrial buildings, or any facility that houses one or more water heaters can benefit from installing water heater timers to make use of off-peak hours. Because older water heaters, 10 years old or more, have lower insulation levels in the tank, installing a water heater timer can significantly reduce costs.

Installing a Water Heater Timer

Water heater timers are simple to install using this five-step process. For installation, you will need a drill and assorted drill bits, a screwdriver, a hammer, a new electrical cable the same gauge as the old one, a wire cutter, wire stripper, a voltage tester, and a pencil. The following are general guidelines to give you an idea of the process. For detailed wiring instructions, refer to the manufacturer’s instruction manual or consult an electrician.

Step 1: Remove Water Heater Timer from its Casing

Make sure your water heater is an electric water heater. Turn off the electricity at the main electrical panel, moving the breaker that controls power to your water heater to the OFF position. Remove the water heater timer from its casing. Using a hammer and screwdriver, knock out the casing’s knock out holes.

Step 2: Mount the Timer Near the Water Heater

Hold the casing firmly against the wall as a template. With a pencil, mark the mounting holes. Drill holes and firmly screw the casing to the wall.

Step 3: Remove the Power Cable from the Water Heater

With a voltage tester, make sure the power to the water heater is off. Remove the main power cable to the water heater and thread it through one of the knock out holes in the casing.

Step 4: Connect the New Cable

Make sure your new cable is the same gauge as the old one. Run the new cable from the casing to the water heater. Strip approximately ½ inch of insulation from each of the wires and connect them to the water heater. For detailed wiring instructions refer to the manufacturer’s instruction manual or consult an electrician. Place the water heater timer in the casing.

Step 5: Connect the Wires to the Timer

Strip approximately ½ inch of insulation from each wire in the casing. Bend the bare wire ends to fit around the corresponding lug. (See manufacturer’s instructions for details.) Hold wires firmly in place as you tighten the screws, securing the wires to the timer. Set the timer and turn the power on.