Home Energy Audit Calculator
Calculate the electricity cost of any home appliance.
Enter wattage, daily usage, and your electricity rate to see daily, monthly, and annual costs.
A home energy audit works one appliance at a time. Run this for each device you are curious about, write the annual figures down, and the list sorts itself: two or three items almost always account for most of the bill, and they are rarely the ones people suspect. The usual surprise is that a 1,200-watt appliance used for ten minutes a day costs less per year than a 15-watt device left on permanently.
Formula:
Annual kWh = (Watts × Hours per day × Days per year) / 1000
Annual cost = Annual kWh × Electricity rate ($/kWh)
What is a kWh? A kilowatt-hour (kWh) is the standard unit for measuring electricity consumption. 1 kWh = running a 1,000-watt appliance for 1 hour. Most electricity bills charge between $0.10 and $0.30 per kWh depending on country and region.
- US average: ~$0.17/kWh
- UK average: ~$0.25/kWh
- Australia average: ~$0.28/kWh
- Canada average: ~$0.11/kWh
Common appliance wattages:
| Appliance | Typical Wattage |
|---|---|
| LED light bulb | 8 – 15 W |
| Laptop computer | 30 – 70 W |
| Desktop PC | 100 – 300 W |
| 40-inch LED TV | 35 – 100 W |
| Refrigerator | 100 – 200 W |
| Dishwasher | 1,200 – 2,400 W |
| Washing machine | 500 – 1,800 W |
| Clothes dryer (electric) | 4,000 – 6,000 W |
| Electric oven | 2,000 – 5,000 W |
| Microwave oven | 600 – 1,500 W |
| Air conditioner (window unit) | 500 – 1,500 W |
| Central air conditioner | 2,000 – 5,000 W |
| Electric water heater | 3,000 – 4,500 W |
| Pool pump | 750 – 2,000 W |
| Electric vehicle charger (Level 2) | 6,000 – 12,000 W |
| Space heater | 750 – 1,500 W |
| Hair dryer | 1,000 – 1,875 W |
| Coffee maker | 750 – 1,500 W |
Tips to reduce electricity costs:
- Switch incandescent bulbs to LED and save about 80% of the lighting energy
- Run dishwashers and washing machines only when full
- Use power strips to eliminate standby (“vampire”) power draw
- Set your water heater to 49°C (120°F). Dropping it 10°C saves 5–10% on water heating
- A refrigerator more than 10 years old may use twice the energy of a modern model
Reading your electricity bill: Your bill should show total kWh consumed and the rate per kWh. Divide your total bill by total kWh to get your effective rate including fees and taxes.
How we build and check this calculator
This calculator runs entirely in your browser, so the numbers you enter stay on your device. The math behind it is written by hand and tested against worked examples and standard references before the page goes live.
SuperGlobalCalculator is independently built and maintained. See how we build and verify our calculators.