How to calculate your home's electricity consumption
Calculating how much electricity an appliance uses is simpler than it seems. You only need three numbers: power, hours of use and the kWh price.
1. Find the appliance power
Look at the rating label (usually on the back or bottom). It shows a value in watts (W) or kilowatts (kW). If it's in kW, multiply by 1000 to get W.
2. Estimate hours of use
Note how many hours per day you use the appliance. Things like the fridge run 24 h, but actual average consumption is much lower than peak power because the compressor cycles on and off.
3. Apply the formula
Energy (kWh) = (Power W × hours) / 1000 Cost (€) = kWh × kWh price
Example: a 2000 W heater used 3 h/day → (2000 × 3) / 1000 = 6 kWh/day. At €0.15/kWh: €0.90/day, €27/month.
4. Add up all appliances
Repeat the calculation for each relevant appliance and add them up. You'll get an estimate of total monthly consumption. Compare it with your bill to spot discrepancies.
Reference consumption table
| Appliance | W | h/day | kWh/día |
|---|---|---|---|
| Fridge A++ | 150 | 24 | 1.10 |
| Air conditioner split | 1200 | 4 | 4.80 |
| Electric oven | 2400 | 0.5 | 1.20 |
| Washing machine 40°C | 1800 | 1 | 1.80 |
| Microwave | 1000 | 0.25 | 0.25 |
| LED TV 50" | 90 | 4 | 0.36 |
| Laptop | 50 | 6 | 0.30 |
| Electric heater | 2000 | 4 | 8.00 |
| Electric water heater | 1500 | 3 | 4.50 |
Average reference values. Real consumption depends on model, age and usage.