Calculating Appliance Electricity Costs in Kilowatt-Hours
Utility companies bill electricity in kilowatt-hours (kWh), not raw watts. One kWh equals 1,000 watts of power drawn continuously for one hour. Understanding this unit lets you convert any appliance's wattage rating directly into a real dollar cost.
Running Wattage vs Peak Surge Wattage
Appliance nameplates often list a peak startup surge wattage that is far higher than steady running wattage. Space heaters, refrigerators, and window AC units draw a brief surge, then settle to a lower sustained draw — use the running wattage for accurate cost estimates.
Delivery Charges & Rate Tiers
Your posted "kWh rate" on a utility bill often bundles generation plus delivery/distribution charges. Always use the all-in blended rate from your latest bill, not just the base generation rate, for the most accurate monthly cost forecast.
Electricity Cost Formula
Cost = (Watts × Hours Used ÷ 1000) × Rate per kWh
Example: A 1,500W space heater run 8 hours/day at $0.16/kWh costs 1.5 × 8 × 0.16 = $1.92/day, or ~$57.60/month.
Common High-Draw Household Appliances
- Central AC / heat pump: 3,000–5,000W
- Electric water heater: 4,000–4,500W
- Space heater: 1,500W
- Desktop gaming PC: 300–750W
- Refrigerator (average running): 100–200W
