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Definition
A kilowatt-hour (kWh) is the standard unit of energy used for electricity billing: one kilowatt of power used for one hour. It's the number you see on your utility bill that determines how much you owe. A kilowatt-hour is distinct from a kilowatt (kW), which measures power or capacity rather than total energy consumed over time. Think of kW as how fast you're using electricity at any moment, and kWh as how much you used overall. Both solar production and home usage are measured in kWh, which is why this unit matters when you compare what your panels generate against what your household consumes. Understanding kWh helps you read your bill, size a solar system, and estimate savings. Actual rates per kWh vary by state, utility, and time of day.
Also Known As
kWh
kilowatt hour
unit of electricity
energy unit
Used in Context
- Your utility bill charges you per kWh, so a household using 900 kWh in a month pays based on that total consumption.
- When sizing a solar system, an installer compares your annual kWh usage against the kWh your panels are expected to produce.
- A solar lead form on Dreamy Leads may ask for your average monthly kWh so quotes reflect your real electricity needs.
What's the difference between a kW and a kWh?
A kilowatt (kW) measures power or capacity—how fast electricity is being used at a given moment. A kilowatt-hour (kWh) measures energy—one kilowatt used for one hour. Your solar system's size is rated in kW, while your production and usage are billed in kWh.
Why does my solar quote ask for my kWh usage?
Because both solar production and home usage are measured in kWh, installers need your usage to size a system that matches what you consume. Knowing your typical monthly or annual kWh helps them estimate how many panels you need and what savings you might see.
How much does one kWh cost?
The price per kWh varies by state, utility, and sometimes the time of day you use power. Your bill shows your specific rate. To find your cost, divide your total charges by the kWh you used, or check the rate listed directly on your statement.
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