What is the difference between kW and kWh?

You may have seen kW and kWh on your electricity bills, on television, or online. But, do you know what they mean, and what the difference is between the two?

Before we go into detail, here are the basics:

  • k stands for kilo, or “one thousand.”
  • W stands for watt, a unit of power.
  • h stands for hour, a measurement of time.

kW vs kWh

kW, short for kilowatt, is 1,000 watts. It is a measure of power or the rate at which electricity flows. So, the more watts an appliance needs to operate, the more electricity it will use. For example, a 100 W light bulb will shine brighter than a 20 W option, but more electricity is required to run it.

kWh, or kilowatt hour, refers to the energy an appliance uses in kilowatts per hour measured by kW x time. If you run the 100 W light bulb for one hour, you will use 0.1 kWh. If you run a 1 kW washing machine for one hour, you will use 1 kWh, and if you run it for two hours, you will use 2 kWh of energy.

Why you need to know the difference between kW and kWh


1. Understand the right size solar power system for your home

It is essential to know the difference between kW and kWh if you intend to install solar power. A solar system’s size is defined by its peak power and is always listed as kW. For example, a 5 kW system can produce a maximum of 5 kW of solar power when the sun is strongest on a perfectly sunny day.

Knowing how much daily energy (kWh) you use on average is an important factor to help identify the correct system size (kW). There are many other factors to determine the right sized system, including roof orientation, location, how much you want to save, and your future plans, such as the purchase of an electric vehicle.

If you’re looking to make the switch to solar, your local Solahart Dealer will provide a free in-home solar assessment to determine which system is best for you.

2. Better monitor your energy consumption

Knowing the difference between kW and kWh allows you to better monitor your energy bills as electricity providers and resellers charge per kWh. By understanding which appliances use the most energy, you can manage your future consumption more effectively.

Going a step further, another way to manage your future consumption is to monitor your energy production and its use within your home with a Solahart Home Energy Management System (HEMS). This system:

  • Brings your connected appliances and energy-generating devices together under one monitoring and control platform.
  • Helps predict solar energy generation from your system by using seasonal and daily weather patterns to decide when it’s best to use high-energy-consumption devices.
  • Allows you to access your energy data, anywhere, anytime using the atHome web App.

Learn more about HEMS today.

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