It is very difficult — if not impossible — to precisely estimate the electricity consumption of an electric water heater, as it depends on many factors: the tank capacity, your household’s hot water usage, and even the layout of your home.
While there is no simple and reliable way to calculate exactly how many kilowatt-hours (kWh) your hot water tank consumes, it is still helpful to understand what factors cause high electricity usage in order to reduce it effectively.
Several elements influence how much electricity your water heater uses:
A larger-capacity water heater naturally consumes more electricity than a smaller one. Choosing the right capacity is crucial for both comfort and energy efficiency.
An oversized water heater will consume a significant amount of energy every day to heat more water than you actually use. Conversely, an undersized water heater will fail to meet your needs, forcing it to reheat water several times throughout the day — leading to higher energy use.
If your water heater is not properly sized or you use a lot of hot water, your energy consumption will increase. Seasonal changes also play a role: we generally consume more hot water in winter than in summer, so it’s best to analyze your overall consumption across the entire year rather than at a single point in time.
The farther your water heater is from your taps, the greater the heat loss through the pipes. Poorly insulated or uninsulated pipes can lead to significant energy waste.
The type of water heater — wall-mounted or floor-standing — does not impact its consumption. However, with small-capacity water heaters* that should be installed as close as possible to the taps, heat loss is much lower and heating times are shorter.
There are several effective ways to lower the electricity consumption of your water heater.
The best way to save money while producing domestic hot water is to install a heat pump water heater (recommended for houses).
This system uses an integrated heat pump to capture calories from the surrounding air — either ambient or outdoor air, depending on its configuration — and uses them as its main energy source. As a result, electricity consumption is drastically reduced. Depending on the model, you can save up to 75% on your energy usage!
Whatever type of water heater you select — electric storage, semi-storage, or heat pump, vertical or horizontal — make sure it offers programmable modes and smart control features. These help you optimize energy use and improve comfort.
Auto/Eco+ Mode (Smart Water Heaters)
This mode automatically adjusts hot water production based on your previous consumption patterns. Only the amount of water you truly need is heated, unlike traditional systems that heat and store the full tank volume every time.
Absence Mode
This function pauses hot water production during periods you specify, such as vacations or long weekends. You can even set your return date so that the water heater reheats just in time for your arrival.
It’s best used for absences longer than 48 hours.
Consumption Monitoring (Connected Models)
If your water heater is connected to the Cozytouch app, you can track your energy use for hot water production on a daily, weekly, or monthly basis. This helps you better understand and manage your actual consumption and costs.
Finally, adopting eco-friendly habits — such as taking shorter showers or washing clothes in cold water — will help reduce your overall energy consumption as well.
Proper maintenance of your water heater is essential. Like a car, regular upkeep ensures efficient operation and helps avoid unnecessary overconsumption.
For example, a scaled heating element (on a water heater with a shielded element) will consume more electricity to heat water efficiently. To prevent this, consider opting for a model with a steatite heating element.
Unlike a shielded element, the steatite version is not in direct contact with water — it’s protected inside an enamelled sheath. This design helps prevent limescale buildup and extends the appliance’s lifespan.
You should also replace the magnesium anode periodically if you have an ACI water heater, to maintain corrosion protection.
*Note: These are not instantaneous water heaters.
**Atlantic no longer manufactures solar water heaters.
