Glossary · Energy, bills & ratings
Kilowatt-hour (kWh)
Also called: kilowatt-hours · MWh · megawatt-hour
The unit on your electricity bill: one kilowatt-hour is 1,000 watts used for one hour, such as a 100-watt bulb left on for 10 hours.
What it means
A kilowatt (kW) is a rate of power, while a kilowatt-hour is energy used over time. Your meter counts kWh and the bill multiplies them by the price per kWh, which may vary by time of day (see time-of-use pricing). Comparing kWh with gas use in therms, cubic metres or gigajoules requires a conversion.
Why it matters in an audit
Twelve months of kWh readings show your baseload and how much electricity goes to heating or cooling, which helps the auditor estimate savings.
Typical numbers
Reference values with their sources. Your energy advisor’s report gives the figure for your own house.
| What | Value | Source |
|---|---|---|
| Conversions | 1 kWh = 3.6 MJ (NIST) = 3,412 BTU (EIA) | nist.gov ↗ |
| To gas units | 1 GJ ≈ 277.8 kWh; 1 therm ≈ 29.3 kWh | Arithmetic from NIST and EIA factors |