Your electricity bill measures energy in kilowatt-hours (kWh), but what does that actually mean? Understanding kWh is the key to knowing which appliances cost the most, how to reduce your bill, and how to compare energy plans.
What Is a Kilowatt-Hour?
1 kWh = using 1,000 watts for 1 hour. A 100 W light bulb running for 10 hours uses 1 kWh. A 2,000 W heater running for 30 minutes uses 1 kWh.
The average US household uses about 900 kWh per month (30 kWh/day). The average EU household uses about 300–400 kWh/month, significantly less due to higher energy efficiency and smaller homes.
Appliance Energy Consumption
- Air conditioner (central): 3,000–5,000 W → 3–5 kWh per hour
- Electric heater: 1,500–2,000 W → 1.5–2 kWh per hour
- Refrigerator: 100–400 W → 1–4 kWh per day (cycles on/off)
- LED light bulb: 8–12 W → 0.1 kWh for 10 hours
- Washing machine: 500 W → 0.5 kWh per load (cold wash)
- Dryer: 2,000–5,000 W → 2–4 kWh per load
Calculating Your Costs
Multiply kWh by your electricity rate. US average: $0.16/kWh. UK average: £0.34/kWh. Germany: €0.35/kWh. Australia: A$0.30/kWh.
Example: Running a 2 kW heater for 8 hours/day at $0.16/kWh costs: 2 × 8 × 30 days = 480 kWh/month = $76.80/month.
Standby power ("vampire load") accounts for 5–10% of household electricity. A TV on standby uses 1–5 W continuously — about 10–40 kWh per year.
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