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To calculate the electricity usage of a water heater it is not that straight forward.

On this page you will find out:

How much electricity does a water heater use

> Water heater electricity cost calculator

Electricity measurement units: Watt, Kilowatt or Kilowatt hour

> How to lower your electricity bill

> What is energy conservation and how does it benefit you and the environment

Alternatively, you may want to fast forward to the water heater electricity cost calculator. 

How much electricity does a water heater use

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

But, a the heater it is not drawing 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 up 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 it is to use a device that can measure the electricity consumption over time.

If your water heater it is plugged to a socket, it is possible to use a plug in power meter to get an exact electricity consumption value. On the video below we are explaining what is a plug in power meter. 

A plug in power meter displaying the power usage of a device

Electricity cost calculator

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

You just 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 euro (or dollars or pounds) per every kWh you consume 

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

A few other examples from our ‘Electricity usage calculators‘ page that may be of your interest:

Fridge electricity usage calculator icon
Freezer electricity usage calculator icon
Dishwasher electricity and water usage calculator icon
Coffee machine electricity usage calculator icon
Coffee machine

Electricity measurement units

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

What is a Kilowatt hour (kWh)

Or you can have a look to 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 to other units

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

Watt (W)
Kilowatt (kW)
Kilowatt hour (kWh)
Kilowatt hour
Power, voltage, current
Power, Voltage, Current

How to lower your electricity bill

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

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

1.- Lower the thermostat

Make sure that the heater is setup to heat up the water to a reasonable temperature. It is pointless to heat up the water so much than then it is needed to be mixed with cold water for having showers of washing the dishes.

The higher the water temperature, the most electricity the water heater will have to use to first heat up the water and after to maintain the temperature.\

2.- Insulate the water heater tank

If your water heater is very old and it is not insulated, it will be losing 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 be losing 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 it is very old, it may be worth to find out the exact electricity usage and if it is too high to consider to buy a new and efficient model.

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 on your energy bills. 

And it also does benefit the environment because conserving electricity prevents any unnecessary waste of natural resources.

Now, at individual level it may not look worth to try to save a few watts here or there. 

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


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

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 euro (or dollars, or pounds, or any other currency) per kWh, we would collectively be saving nearly 6000 euro 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.

Have a look to this page for more information about the amount of resources needed to produce electricity.

In any case it is clear that small energy savings do really count when looking into the bigger picture.

If you are looking for ideas to save electricity at home, have a look to this YouTube video were we show some useful tips to reduce the electricity usage at home and decrease the electricity bill. 

Two pie charts showing what home appliances and devices are using the most electricity at home.

We hope that you have found the information on this page informative and of value. 

If so, please consider to share or subscribe to our newsletter.

We dedicate a considerable amount of time and effort to create content and your support and engagement will encourage us to keep moving forward.

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