Room heating · Space heater energy use
A 1500 W electric heater uses 1.5 kWh in an hour at full power. The hourly cost is 1.5 times your electricity price per kWh.
Use the power setting and active heating time to compare your room heater, ceramic fan heater or oil-filled radiator.
A 2000 W heater uses 2 units per full-power hour; a 1000 W heater uses 1. This answers the arithmetic question. Whether either keeps your room comfortable depends on heat loss, conditions and controls.
Calculate electricity use before estimating the bill
Energy cost = kWh × your applicable unit rate
Imagine a 1500 W heater runs at full input for four hours a day over 30 days: 1.5 × 4 × 30 = 180 kWh. This is an original hypothetical schedule, not an average household or a recommendation to run a portable heater unattended.
| Assumed input | Units per hour | Units per month |
|---|---|---|
| 1000 W | 1.0 | 120 |
| 1500 W | 1.5 | 180 |
| 2000 W | 2.0 | 240 |
Use the selected setting, not the maximum rating, if the manual gives a different input for that setting. Two heaters at the same setting need their quantities counted separately.
Cost per hour: examples in five currencies
The following rates are invented teaching inputs, not current tariffs, national averages or exchange-rate conversions. Replace them with your own bill's marginal energy price.
| Example market | Assumed price/kWh | Energy cost/hour |
|---|---|---|
| Pakistan | PKR 50 | PKR 75 |
| US | USD 0.20 | USD 0.30 |
| UK | GBP 0.25 | GBP 0.375 |
| Canada | CAD 0.15 | CAD 0.225 |
| Australia | AUD 0.30 | AUD 0.45 |
Fixed charges generally do not increase just because this heater runs. Slabs, time-of-use prices, taxes and adjustments can affect the extra charge. Split use by rate period when needed. The same energy formula applies to “space heater electricity cost” and “electric heater running cost.”
What if the thermostat switches the element off?
Suppose a hypothetical 1500 W element heats for 30 minutes in each hour. Over four hours, active time totals two hours: 1.5 × 2 = 3 kWh, instead of 6 kWh at continuous input.
The 50% on-time is an assumption, not a saving promised by an “eco” button. Fan or control power may remain when the element stops. Use whole-session measured kWh if available through a method explicitly permitted by the heater manufacturer and suitable for the load.
Room temperature, open doors and draughts affect the on-time. Do not choose a universal “half the bill” multiplier. To compare two evenings, log start/end times, setting, weather and occupied room conditions.
Oil-filled versus ceramic: what actually changes?
For equal total electrical input, ordinary resistance heaters release approximately that energy as heat within the room. An oil-filled radiator stores and releases heat differently from a fan heater; its warmth after switching off came from electricity used earlier. It does not create free additional energy.
Australian government heating guidance discusses portable electric heaters and reverse-cycle systems. A heat pump is a different technology, so do not extend the resistance-heater comparison to every heating option. Comfort, room coverage, noise, thermostat behaviour and operating time still matter.
International manufacturer links to check specifications
- De'Longhi US Capsule HFX30C15.W: the manufacturer lists 1500 W. Use its manual for approved operation.
- Dimplex UK DX-series fan heaters: the manufacturer describes a 2 kW model with thermostat settings.
- De'Longhi's setting guide: illustrates why minimum, middle and maximum settings need different inputs.
These are manufacturer references, not affiliate links or independently tested recommendations. A US-market unit is not automatically suitable for a Pakistan, UK or Australian socket, voltage or supply. Buy a correctly rated local-market model and check local warranty support.
Can heating one room reduce the whole bill?
Only if it avoids enough other heating to offset the added electricity. Leaving central heating unchanged and adding a space heater can increase total use. Record both systems' energy changes over comparable conditions; do not compare different-sized heated spaces as if the comfort service were identical.
Use your own electricity rate
Open the electricity bill and device estimator
Read how to calculate appliance electricity units and our methodology and limits. The device estimator calculates electricity; it does not turn LPG kilograms into an electricity bill.
Prepared 2 November 2026. Arithmetic examples are original and hypothetical. Product wattages were checked against the linked manufacturer pages; no hands-on product test, universal room-size claim or guaranteed saving is implied.
Choose the right calculation for your next question
Buying LPG by the kilogram? The gas heater consumption guide converts a model's grams per hour into cylinder runtime and fuel cost.
Heating water instead? Read the electric geyser and water-heater guide to distinguish element-on time from time connected to power.
For a household-wide check, use the seven-day energy worksheet before deciding which appliance to replace.
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