What Is a Kilowatt-Hour?

Kilowatt-hours: everything you need to know

A kilowatt-hour (kWh) is a unit of energy used to measure electricity consumption. It represents the amount of energy used when one kilowatt (1,000 watts) of power is consumed for one hour.

For example, if you have a 100-watt light bulb and leave it on for 10 hours, it will use 1 kilowatt-hour of electricity. 100 watts multiplied by10 hours is equal to1,000 watts, or 1 kilowatt-hour.

Electricity providers measure your home’s energy consumption in kilowatt-hours and calculate your bill with your usage and energy charge.

What’s the difference between a kilowatt-hour and a kilowatt?

The difference between a kilowatt (kW) and a kilowatt-hour (kWh) lies in what they measure:

1. Kilowatt (kW): Kilowatts are a unit of power. They measure the rate at which energy is being used at any given moment. One kilowatt equals 1,000 watts. For example, if an appliance is rated at 1 kilowatt, it consumes 1,000 watts of power while running.
2. Kilowatt-hour (kWh): Kilowatt-hours are a unit of energy. They measure the total amount of energy consumed over a period of time. A kilowatt-hour equals the amount of energy used by a 1 kilowatt appliance running for one hour. It’s the measurement used on electricity bills to show how much electricity you’ve used.

In short, kW measures power (the rate of energy use), while kWh measures energy (the amount of electricity used over time).

What can 1 kilowatt-hour power at home?

One kilowatt-hour can power different household appliances and technology for different lengths of time because each device requires a unique wattage to operate. Here are some common examples of what 1 kWh can power in a home:

1. 10-watt LED light bulb for about 100 hours.
2. Refrigerator (average modern energy-efficient model) for about 24 hours.
3. Ceiling fan (50 watts) for about 20 hours.
4. Laptop (50 watts) for about 20 hours of use.
5. Microwave oven (1,000 watts) for about 1 hour.
6. Washing machine (500 watts) for 2 hours of operation (without the heating element for hot water).
7. Air conditioner (window unit) (1,000 watts) for about 1 hour.
8. Hair dryer (1,500 watts) for about 40 minutes of use.
9. Space heater (1,500 watts) for about 40 minutes.

The electronics in your home may require different wattage to operate, but these examples can give a rough idea of how far one kilowatt-hour can go.

What are megawatts and gigawatts?

Megawatts (MW) and gigawatts (GW) are larger units of power than kilowatts (kW), used to measure much larger amounts of electrical energy. Here’s the difference:

1. Megawatt (MW):
   • A megawatt equals 1,000 kilowatts, or 1 million watts.
   • It is commonly used to describe the capacity of power plants or the consumption of large industrial facilities. For example, a wind turbine might have a capacity of 2 MW, meaning it can produce up to 2 megawatts of power when operating at full capacity.
2. Gigawatt (GW):
   • A gigawatt equals 1,000 megawatts, or 1 billion watts.
   • Gigawatts are used to describe the power capacity of very large power plants or the total energy output of entire regions or countries. For instance, a large nuclear power plant might have a capacity of 1 GW, and the total energy consumption of an entire city might be measured in gigawatts.

To summarize:

• 1 kilowatt (kW) = 1,000 watts (w)
• 1 megawatt (MW) = 1,000 kilowatts (kW)
• 1 gigawatt (GW) = 1,000 megawatts (MW) = 1,000,000 kilowatts (kW)

What uses the most kilowatt-hours in your home?

The four categories that use the most energy at home in Texas are: heating and cooling, water heating, appliances and electronics, and lighting.

• Heating and cooling – 53%
• Water heating – 20%
• Appliances and electronics – 20%
• Lighting – 10%

Energy use varies by home depending on size, location and climate, human behavior, the number of people living in a space, and efficiency of appliances.

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