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Water heater power consumption and electricity cost

The power consumption of a water heater can vary depending on its size, type, and efficiency.

To calculate the electricity cost of running an electric water heater, you need to know its power consumption in watts and the cost of electricity per kilowatt-hour (kWh) in your area.

How much power and electricity does a water heater use

Depending on the model, a water heater will use between 1.5 and 10 kWh of power.

It is possible to get the water heater power consumption from its specifications label and, with that value, calculate the approximate electricity cost. For that, we have left a handy calculator in the next section.

But, a heater does not draw electricity all the time. A water heater stops drawing electricity once the water is hot enough and starts drawing electricity again once the water heat drops below a predetermined threshold or if it needs to heat incoming cold water. 

Also, the electricity consumption will depend on the water heater settings so the only way to get an accurate value for the electricity consumption of a water heater is to use a device that can measure the electricity consumption over time.

If your water heater is plugged into a socket, it is possible to use a plug-in power meter to get an exact electricity consumption value. In the video below, we explain a plug-in power meter. 

Have a look at this YouTube video for more information.

Plug in power meter

Water heater electricity cost calculator

The calculator below can be used to calculate approximate the power and cost consumption of a water heater over time.

You need to adjust the values in the PARAMETERS section to your requirements and the calculator will automatically display the RESULTS section.


For example, if your water heater:

> It has a power consumption of 3 kWh

> It is in use 4 hours and 320 days per year

> You are paying 0,217 euros (or dollars or pounds) per every kWh you consume 

You will be paying around 833 euros (or dollars, pounds, or…) per year in electricity costs.

Here are a few other examples from our ‘Electricity usage and electricity cost calculators‘ page that may be of your interest:

How to lower your electricity bill of a water heater

A water heater will be one of the largest electricity usages of any household, especially during winter.

Here there are a few tips to save electricity on a water heater:

1.- Lower the thermostat

Ensure the heater is set up to heat the water to a reasonable temperature. It is pointless to heat the water so much that it needs to be mixed with cold water for showers of washing the dishes.

The higher the water temperature, the more electricity the water heater will use to heat and maintain the temperature.\

2.- Insulate the water heater tank

If your water heater is very old and is not insulated, it will lose heat through the tank, and the heater will have to keep using electricity to maintain the water temperature.

3.- Insulate the water pipes

Apart from having a well-insulated water tank, it is important to have well-insulated pipes. Otherwise, the pipes will lose heat, and if the cold water and hot water pipes are very close together, this will have a negative effect.

Well insulated hot water pipes
Infrared thermal imaging of a well insulated hot water pipes

4.- Buy an efficient water heater

If your heater is very old, it may be worth finding out the exact electricity usage, and if it is too high, consider buying a new and efficient model.

Water heater electricity usage FAQ

How many watts does a water heater use?

Depending on the water heater model, between 1.5 and 10 kWh per hour.

If you want to know the exact power consumption of a water heater, the best option would be to use a plug-in power meter and measure the power usage over time.

How much energy does a water heater use?

As explained in the question above…

Depending on the water heater model, between 1.5 and 10 kWh per hour.

If you want to know the exact power consumption of a water heater, the best option would be to use a plug-in power meter and measure the power usage over time.

Electricity measurement units

Not everybody is familiar with terms like Watts, Kilowatts, or Kilowatt hours, so if you would learn more about them, look at this YouTube video we have prepared about this topic.

What is a Kilowatt hour (kWh)

Or you can have a look at this electricity measurement units calculators to get a better understanding of:

> What is a Watt (W), and how to transform Watts into Kilowatts

> What is a Kilowatt (kW), and how to transform Kilowatts into Kilowatts hour

> What is a Kilowatt hour (kWh), and how to transform Kilowatts hours into other units

> What are Power (P), Voltage (V), and Current (I)

Watt (W)
Watt (W) wattage calculator
Kilowatt (kW)
Kilowatt (kW) calculator
Kilowatt hour (kWh)
Kilowatt hour (kWh) calculator
Power, voltage, current
Power, voltage, current calculator

Water heaters and energy conservation

Energy conservation can be defined as the decision and the act of using less energy.

Energy conservation both benefit you and the environment

The act of saving and conserving electricity does benefit you because you will be paying less for your energy bills. 

And it also benefits the environment because conserving electricity prevents unnecessary waste of natural resources.

At the individual level, it may not look worth trying to save a few watts here or there. 

Still, every little one counts, and if hundreds or thousands of us save a little every time, it will make an important contribution towards conserving our natural resources.


For example, if 9000 households save as little as 10 Watts per day (0,01 kWh), that would add to 32850 Kilowatt hours (kWh) saved annually. 

9000 households x 0,01 kWh per day x 365 days per year 

32,850 kWh saved per year

That is a considerable amount of electricity, but let’s add additional perspectives for clarity:

> Assuming an average cost of 0,18 euros (or dollars, or pounds, or any other currency) per kWh, we would collectively save nearly 6000 euros per year.

> To produce 32,850 kWh of electricity, it is necessary to use around 17 metric tons of coal or 56 barrels of residual fuel oil.

Look at this page for more information about the resources needed to produce electricity.

In any case, small energy savings do count when looking into the bigger picture.

Proven ways to save electricity at home

Suppose you are looking for ideas to save electricity at home; look at this YouTube video. We show some useful tips for reducing electricity usage at home and decreasing the electricity bill. 

How to save electricity at home
How to save
How to save
How to earn
How to earn


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