What Is a kWh?
1 min read
Quick Answer
A kWh (kilowatt-hour) measures electricity consumption over time. One kWh equals 1,000 watts used for one hour. It's what electric companies bill you for—the average US price is about $0.16 per kWh.
Key Takeaways
- Watts measure instantaneous power draw, while kilowatt-hours measure total energy consumed over time.
- Some utilities have tiered rates—first 500 kWh might cost less than the next 500.
- Time-of-use rates vary by time of day—peak hours cost more.
Explanation
Watts measure instantaneous power draw, while kilowatt-hours measure total energy consumed over time. A 100-watt light bulb running for 10 hours uses 1 kWh (100W × 10h = 1,000Wh = 1kWh).
Your electric bill shows total kWh used during the billing period. To calculate cost: kWh × rate per kWh = cost. If you used 1,000 kWh at $0.16/kWh, your bill would be $160.
Understanding kWh helps you estimate appliance costs. A 1,500W space heater running 8 hours uses 12 kWh, costing about $1.92 per day at average rates.
Things to Know
- Some utilities have tiered rates—first 500 kWh might cost less than the next 500.
- Time-of-use rates vary by time of day—peak hours cost more.
- 1 kWh = 3,412 BTU, useful when comparing to gas appliance costs.