How much electricity does a heater use? A transparent calculation
Convert heater power into kWh, allow for thermostat cycling and compare consumption with your own tariff without promising the same monthly bill for every home.
A “2000 W” label describes power, not the price of a month's heating. You also need actual heating time and an appropriate price per kilowatt-hour. Begin with a manageable period: one evening or a few comparable days. That is more useful than a confident monthly figure inferred from a product photograph.
Convert the power rating
Divide watts by one thousand: 2000 W equals 2 kW. For continuous operation, multiply power by time. A 2 kW element running for five uninterrupted hours consumes a calculated 10 kWh. This is a mathematical example, not a measurement of your appliance.
At a hypothetical variable all-in price of €0.20 per kWh, those 10 kWh would cost €2. The price illustrates the formula; it is not a current Estonian tariff. Substitute your own relevant price components. Do not assign a fixed monthly standing charge to a single evening without explaining the allocation.
Allow for the thermostat
Five hours plugged in does not necessarily mean five hours heating at full power. A thermostat can switch the element off, and the appliance may use a lower setting. A calculation based on rated power is useful as a continuous full-load scenario, but is not a substitute for measuring consumption.
Use suitable metering or information that separates this appliance from other loads. A plug-in meter must be rated for the load and compatible with the heater's instructions. Do not add an unsuitable adaptor merely to obtain a reading.
Compare similar conditions
- The same room and target temperature.
- A comparable observation period.
- A record of opened doors and windows.
- Other sources of heat in the room.
- A separation of fixed charges from consumption-dependent costs.
Do not promise savings solely because an appliance has a new casing or marketing name. Room conditions and controls can change its running time. A useful comparison explains what changed rather than attributing the entire difference to one device.
Check safety first
Follow the manufacturer's requirements for the socket, clearances and use. Never cover the heater or dry clothes on it. Stop using it if there is an overheating smell, cable damage or a hot connection, and have the cause assessed by a competent person.
Keep a record of power, operating time, measured consumption and the price used. Someone reading that record should be able to repeat the calculation and understand why two evenings might produce different results.
Sources
Prepared 6 November 2026. The image is an AI-generated illustration.