A watt (W) measures the amount of power required to run a device or appliance.
A kiloWatt hour (kWh) measures that amount of power over a period of time, and that's the measurement your electricity provider uses to charge your household for electricity used.
To clarify, 1kWh is 1000 watts used for one hour. If a device requires 250W to operate, it consumes 0.250kWh per hour. The longer the device runs, the more kWh it consumer.
Here's a good example of how it works: If you use a 100-watt light bulb, it runs 10 hours to add 1kWh of energy to your bill. If you use a more efficient 40W LED bulb to generate the same amount of light, it runs 25 hours to add 1kWh to your bill.
So, to save energy and money you'll want to:
- Use devices only when needed (and remember that some devices, like some consumer electronics, continue to consume energy even when they are inactive -- see ALWAYS ON articles), and
- Invest in energy efficient devices and appliances