Watts to kWh
kWh = (W ÷ 1,000) × hours × load factor. Multiply kWh by your electricity price to estimate energy cost.
❄️ Worked example
How much electricity does a air conditioner use?
Start with a transparent example, then replace the assumptions with your own wattage, operating time and electricity price.
5.04 kWhper day of use
30.24 €per month at 0.20 €/kWh
Worked example
1200 W × 7 h/day × 60 % load factor × 30 days.
151.20 kWh/month · 362.88 €/year
This is an energy-only estimate. Your bill can also include standing charges, taxes and other household consumption.
Typical reference range
Use the label, manual or manufacturer data for your exact model whenever possible.
| Type or situation | Indicative reference |
|---|---|
| Small efficient unit | 500–800 W |
| Typical domestic split | 800–1,500 W |
| Large unit / multisplit | 1,500–3,000+ W |
What changes the result?
Rated watts are only one part of the calculation.
Measure when possible
Thermostats, compressors, inverter control and programmes can make real consumption lower or higher than a simple maximum-power estimate.
Practical checks
- Use a sensible set point and avoid large temperature swings.
- Clean accessible filters regularly.
- Measure over several hours because inverter systems modulate.
Compare more appliances
Return to the appliance library or use the general electricity calculator for any device.
NEXT STEP