What's a kWh?

Posted 06/10/2015 by E.ON

Did you know that on average, the average household wastes energy equating to approximately 16 per cent of its annual electricity bills? That’s crazy, right?

It’s much easier to work out how to reduce your energy use once you understand a few things about your bill. And that starts with the kilowatt.

The kilo-what? Exactly. It’s estimated that one in five of us don’t know what’s meant by those funny ‘kW’ and ‘kWh’ terms that appear on our statements. But it’s one of the most important parts of understanding how you’re charged for the energy you use. So grab a cup of tea and read on to find out everything you need to know…

light bulbs - E.ON 

What’s a kilowatt?

A kilowatt (shown using kW) refers to the rate that energy is produced or consumed. The watt is a measurement of power. Devices consume electricity at a rate specified in kW. So a 60-watt light bulb requires - you guessed it - 60 watts of power to make it light up. And there are 1,000 watts in a kilowatt. Simple.

OK, so what’s a kWh?

A kilowatt hour (shown as kWh) calculates the amount of energy you’re using. It’s a unit of measurement that totals the amount of energy you would expend by running a 1,000-watt appliance for a one hour period. rel="noopener noreferrer" So if you turned on your 200 watt desktop computer, it would take five hours of surfing the internet to amount to 1 kWh of energy.   

coffee on gas hob - E.ON 

I’m starting to get it. But why do I need to know this?

Because once you do, you’ll realise just how much additional, redundant energy you’re using with certain devices. The fact that bills are measured in kWh means that if you’re leaving a TV on standby, keeping a mobile phone charger plugged in even though the phone is fully charged, or putting far more water in the kettle than you need, it’ll cost more. These devices are still using power and adding kWh costs to your energy bill. The price of a kWh varies depending on your tariff - you’ll be able to find how much you’re paying by looking at your bill.

Right, I get it. And I don’t want to pay more than I need. So give me some examples.

Certainly. Let’s head into the rel="noopener noreferrer" lounge. That plasma TV requires around 300-400 watts, so watching three hours will take you to a cool 1 kWh. A rel="noopener noreferrer" ten-hour Call of Duty binge on the X-Box will take you to that amount too. Even leaving your games console on standby will use 1kwh of energy within four or five days.

Still want more examples? Then take a look at our natty infographic below to really get to grips with how kWhs work…  

How many kilowatts it takes to do certain things

So what now?

Now you can read your bill with confidence. And know just how much energy you’re using to watch all those cat videos (time well spent, of course). Managing and controlling your energy use can help you reduce your bills and become more energy efficient. So if you’d rather keep the pennies in your pocket, then head over to our saving energy page - armed with all your new kWh knowledge - to find out even more.

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