Appliance Energy Calculator — Formula

## How to Calculate Appliance Energy Cost

Every electrical appliance has a wattage rating that determines how much energy it uses.

### Formula

**Annual kWh = Wattage * Hours/Day * Days/Year / 1,000**

**Annual Cost = Annual kWh * Rate per kWh**

### Common Appliance Wattages

- Space heater: 1,500W
- Hair dryer: 1,200W
- Refrigerator: 150W (average)
- LED bulb: 10W
- Desktop computer: 200W

Esempio Risolto

A 1,500W space heater used 3 hours/day for 365 days at $0.15/kWh.

  1. Annual kWh: 1,500 * 3 * 365 / 1,000 = 1,642.5 kWh
  2. Annual cost: 1,642.5 * $0.15 = $246.38
  3. Monthly cost: $246.38 / 12 = $20.53
  4. Daily kWh: 1,500 * 3 / 1,000 = 4.5 kWh