How To Install An Electric Water Heater Step By Step

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An electric water heater uses electricity as the energy to heat the water. The current gets passed through a resistor and power dissipates at it. The dissipated energy is used to heat the water. At the places where gas is unreachable, or the electricity rate is affordable, people use electric water heaters. In this article, we are going to discuss how to install an electric water heater.

Electric heaters are very common. According to a report, in the US, nearly 39% of the water heaters are electric water heater, and 53% are gas water heaters. However, in East South Central and Middle Atlantic, the usage of an electric water heater is more than 60%. In this article, we will discuss how to install an electric water heater with a detailed step by instructions. However, before discussing how to install an electric water heater, we will give you quick steps to remove your old electric water heater. To remove your old water heater, follow the steps give below.

Steps to remove old electric water heater

  1. Turn off the power of the radiator from the main circuit board. After switching off the breaker, check with a multimeter or circuit tester whether the power is switched off or not. If it is off, then we are ready to go safely.
  2. Disconnect the wires from the old heater and makes sure to remember the phase, neutral and ground. You can place a mark on the wires to remember. Now, set the wires aside.
  3. Close the inlet valve, and now it’s the time to empty the tank. Open the hot water faucet at your home and drain the water. The remaining water can get exhausted by connecting a garden hose to the drain valve.
  4. Now remove the discharge pipe with a spanner.
  5. Remove the water inlet and outlet pipes and remove your old water heater.

How to install an electric water heater?

After the successful removal of your old water heater, it is time to place the new water heater. If you are going to replace your water heater, then check the operating voltage and wattage of the new water heater. Make sure that the connection wires can bear the current of your new water heater. You can see the wattage at the nameplate of your water heater and buy wires and circuit breakers accordingly. Now here are the steps on how to install the electric water heater.

1)     Place your new water heater

Place your new water heater at the right place, just below the water lines.

2)     Connect the discharge pipe

Now connect the discharge pipe to T&P (Temperature and Pressure) relief valve. The T&P relief valve generally located at the top of the heater or any side of the heater. After finding the valve connect the discharge pipe. You can even use your old discharge pipe if it is in good condition. If you are using a mature tube, then clean the threads of the tunnel and apply plumbing tape. You can connect the other end of the pipe to a floor drain or place a water bucket under it.

3)     Waterline connection

Now it’s time to join the water pipes to your heater. The water inlet and outlet remain located at the top of the heater. You can enter a flexible hose with the tubes. Flexible hoses are easy to fit, and they save from leakages due to the earthquake. Now identify the water inlet and outlet on your heater. Use the connectors to connect the flexible hose. Apply plumbing tape on the connectors and tight it with a spanner.

4)     Check for Leakage

After joining the pipe with the tube, open the inlet water valve. Notice if there is any leakage or not. If there is any leakage, then tighten the nut using a spanner. If there is still any leakage, then close the valve. Open the fitting and apply plumbing tape properly. Apply at least four rounds of plumbing tape and use pipe dope. Now fix the pipe again; it will probably not leak this time.

5)     Fill the tank

After ensuring that there is no leakage, fill your tank. For this open, the hot water faucet, and then the inlet valve. The air will come out from the faucet and fill the tank until there is no air left in the tank. The water will flow without any hindrance from the faucet when there is no air in the tank.

6)     Connect the wires

Now find the terminal box and open it using a screwdriver. Connect the cables with the right pair. Close the terminal box and turn on the power from the main circuit board. The heater will start heating the water. It will take several hours to heat the water, so be patient.

7)     Temperature Adjustment

You can adjust the temperature by the thermostat. It is usually covered, and you can remove the covering with a screwdriver.  The recommended temperature is 120˚F.

Questions and Answers

What will happen if the wire used cannot bear the current?

If the used wire has rated current lower than the heater current, the wire will become hot. It will damage the insulation and can cause a short circuit as well. Make sure that you are using the right wire cable as recommended by the manufacturer.

Why is earthing/grounding necessary for water heaters?

Earthing/Grounding can save you from shocks. The body of the water heater usually made of steel. If there is any insulation breakage in the radiator, then there is a probability of getting a shock. So, it is necessary to ensure the grounding connection for safety purposes.

Can we use earthquake straps to protect the electric heater?

Yes, we can use earthquake straps to protect from earthquake damage. The straps are tied with the walls so that the heater remains at its place.

How can we calculate the amperage of an electric water heater?

You can calculate the current required by dividing the wattage with the voltage at your home. For example, if the voltage at your home is 240V and the water heater has a wattage of 4500W, then the current will be 4500/240= 18.75A.


It is easy to install a new electric water heater. All you need to do is to follow instructions on how to install an electric heater. If you are not sure about the wire and circuit breaker sizing, then contact an electrician for that or use the manufacturer’s recommended ratings.