How the Appliance Energy Calculator Works
This tool lets you calculate precisely how much energy an appliance consumes and what it costs you per year on your electricity bill. Simply enter the wattage, hours of use, and electricity price to get an accurate estimate.
The Energy Consumption Formula
The calculation is simple but fundamental:
Consumption (kWh) = Power (kW) x Hours of use x Days
The result in kWh (kilowatt-hours) is the unit used for billing electricity. Multiplying kWh by the unit price gives you the actual cost of running the appliance.
Average Wattage of Common Appliances
| Appliance | Avg. Power | Typical Use |
|---|---|---|
| Refrigerator | 100-150 W (intermittent) | 24h/day |
| Washing machine | 500-2,200 W | 1h/cycle |
| Dishwasher | 1,800-2,400 W | 1.5h/cycle |
| Electric oven | 2,000-2,500 W | 1h/use |
| Air conditioner | 800-2,500 W | 6-8h/day summer |
| TV | 50-150 W | 4-5h/day |
CO2 Emissions
Each kWh of electricity produced in the US generates on average about 0.39 kg of CO2 (EPA eGRID 2023). This factor accounts for the national energy mix including fossil fuels and renewables.
How to Save on Energy Costs
- Choose efficient appliances: the difference between high and low efficiency can be 40-60% in annual consumption
- Use off-peak hours: evening and weekend electricity often costs less
- Eliminate standby power: a power strip with a switch can save $50-100/year
- Regular maintenance: a clean AC filter reduces consumption by up to 30%