How Much Does It Cost to Run an Electric Water Heater?

Every hour the heating element is on, a 4,000 W heater uses 4 kWh: about $0.73 in the US, £1.05 in the UK, €1.45 in Germany, €0.99 in France, and €1.26 in Italy. The element doesn't run all day; it switches on when you draw hot water or when the tank cools, and off again once the water is back at temperature.

Around 3 hours of heating a day, or 12 kWh, is a reasonable figure for a busy household with a tank heater. That works out at about $66.25 a month in the US, £96.02 in the UK and €131.98 in Germany. A single person taking short showers may use half as much; a large family can use more.

Costs usually rise in winter. The cold water entering the tank is colder, so it takes more energy to heat, and people tend to take longer, hotter showers.

In the US and Canada, electric storage tanks of about 150–300 litres (40–80 gallons) usually have two 240 V elements of about 4,500 W each, wired so only one runs at a time. In the UK and Ireland, a hot water cylinder is often heated by a 3,000 W immersion heater, sometimes on a cheaper off-peak tariff.

In Pakistan, India and other South Asian countries, smaller wall-mounted storage heaters known as geysers are common, usually rated at about 1,500–2,500 W. Many people switch them on only before bathing, which keeps daily use lower than a tank that stays hot all day.

Tankless or instant heaters, including electric showers, heat water only as it flows. They draw far more power while running, often 3,000–10,500 W and much more for whole-house units, but have no tank losing heat between uses.

A heat-pump water heater moves heat from the surrounding air into the water instead of making it with an element. It typically delivers two to three or more units of heat for each unit of electricity, so it usually uses well under half the electricity of a standard electric tank for the same hot water.

They cost more to buy and need space and airflow around the unit, and most include a backup element for times of very high demand. For households with high hot water use, the running-cost saving is usually the biggest of any water-heating upgrade.

The amount of hot water you use matters most: long showers, baths and hot washes add up quickly. The thermostat setting, how well the tank and pipes are insulated, and whether the heater keeps water hot all day also make a large difference.

A storage tank loses some heat all the time, even when nobody uses hot water, and the element switches on to make up for it. Older or poorly insulated tanks lose more.

Ranges are typical for heaters on sale in 2026. Your heater's exact rating is on its label; use that number and your own heating hours in the calculator.

• Use a timer so the water is heated shortly before you need it, rather than kept hot all day.
• Don't set the thermostat hotter than you need. Many heaters are set higher than necessary.
• Insulate the tank (if it isn't factory-insulated) and the first few metres of hot water pipe.
• Take shorter showers, fit a low-flow showerhead and fix dripping hot taps.
• On an off-peak or time-of-use tariff, heat the tank in the cheapest hours.
• When it's time to replace the heater, consider a heat-pump model.

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