A kilowatt-hour (kWh) is a unit of energy used to measure electricity consumption over time. It represents the amount of energy used when a 1,000-watt (1 kilowatt) device runs for one hour.

Kilowatt-hours are the standard unit utilities use to measure and bill electricity usage in homes and businesses.

What is a kilowatt-hour?

A kilowatt-hour is a measure of energy, not power. It shows how much electricity is used over a period of time rather than how quickly it is used.

For example, using a 1,000-watt appliance for one hour equals 1 kWh of electricity.

This unit is commonly used on utility bills to track total electricity consumption.

Kilowatt vs. kilowatt-hour

Kilowatts (kW) and kilowatt-hours (kWh) are related but measure different things:

• Kilowatt (kW): A measure of power (how much electricity is being used at a moment)

• Kilowatt-hour (kWh): A measure of energy (how much electricity is used over time)

Understanding this difference helps explain how electricity usage adds up throughout the day.

How kilowatt-hours are used in your home

Kilowatt-hours measure how much electricity your home uses over time.

For example:

• A 100-watt light bulb running for 10 hours uses 1 kWh

• A 1,000-watt appliance running for 1 hour uses 1 kWh

Electric utilities track total usage in kWh to calculate monthly energy bills.

Why kilowatt-hours matter for solar energy

Kilowatt-hours are also used to measure how much electricity a solar system produces.

For homeowners, this helps compare:

• How much energy your solar system generates

• How much electricity your home uses

• How much energy is drawn from or sent back to the grid

This makes kWh a key metric for understanding overall energy usage and system performance.

Kilowatt-hours for homeowners

For homeowners, kilowatt-hours provide a simple way to track and understand energy use.

Electricity bills typically show total monthly usage in kWh, which can vary based on home size, appliance usage, and seasonal demand.

With solar, energy production is also measured in kWh, and monitoring tools like the Sunrun app can help track how much energy is produced and used throughout the day.