What is a kilowatt hour? Your questions answered

If you’ve looked at your energy bill lately, you’ve probably come across the term ‘kilowatt hour’. It’s a confusing piece of jargon that trips may people up. In this article, we’ll explain what a kilowatt hour is and answer some other common questions.

What is a kilowatt hour?

Put very simply, a kilowatt hour (or kWh) is a unit of energy. Much like you pay for petrol by the litre or phone calls by the minute, you pay for gas and electricity by the kilowatt hour.

electricity meter
A meter displaying electricity use in kWh. Image source.

When you’re shopping around for gas & electricity, suppliers have to quote their prices in pence per kilowatt hour (Ofgem says so). This makes it easier to compare prices and find a good deal.

For those interested in the technical definition, here it is:

1 kilowatt hour is the amount of energy a 1kW device would use if it was run for one hour – approximately 3.6 megajoules.

For example, a 1 kW heater left running for 1 hour would consume 1 kWh (or 1 unit) of energy.

What is the cost per kilowatt hour?

There isn’t a standard price – it depends on both your energy supplier and the tariff you are currently signed up to.

Unit prices for electricity can range from around 12-18 pence per kWh. Gas is around 3-4 pence per kWh.

Note that you also pay a standing charge with most energy tariffs – you can find more information about standing charges here.

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

A kilowatt is a unit of power. The kilowatt (kW) rating of an appliance describes how quickly it uses energy.

A kilowatt hour is a unit of energy. It describes an amount of energy consumed.

Put it this way – if kilowatt was like the speed of a car, a kilowatt hour would be how far it has travelled.

How do I find out how many kWh I use?

Find out my kilowatt hour use

If you are shopping around for a new energy supplier, it’s useful to know how many kWh your home uses in a month. You can get this information from your current provider – either by looking at a paper bill or by checking your online account.

If you can’t find your exact usage, you can still compare prices using something called Typical Domestic Consumption Values – or TDCVs.

TDCVs are calculated by Ofgem using data from typical households, as shown below:

Fuel Usage kWh (annual)
Gas Low 8,000
Medium 12,000
High 17,000
Electricity Low 1,900
Medium 3,100
High 4,600

Source: Ofgem

For example, a small family living in a 3-bedroom house would probably be classed as a ‘medium use’ home. They could expect to use around 12,000 kWh of gas and 3,100 kWh of electricity in a year.

How do I reduce my energy consumption?

Concerned that your kWh use is too high and costing too much? There are two things you can do:

  1. Claim a free smart meter – this will help you monitor your energy use and take control of your spending.
  2. Switch to a cheaper energy supplier. Eversmart Energy offer some of the best value energy tariffs on the market. You can enter you details and get a quote in under two minutes here.

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