Gas & Electricity

What is a kilowatt-hour (kWh)?

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Image Mark Whelan
Staff Writer

A kilowatt-hour (kWh) is the unit of measurement used by gas and electricity suppliers. One kilowatt-hour is equivalent to 1000 watts of energy used for 1 hour. For example, a 100-watt lightbulb switched on for 10 hours uses one kWh of electricity.

What does 1 kilowatt-hour get me?

On average, Irish households consume 11.5 kWh of electricity and 30.1 kWh of gas per day. That's about 350 kWh of electricity and 917 kWh of gas every month.

One kWh will get you about 10 minutes in an electric shower or one cycle of your washing machine or dishwasher.

About 30 mins of tumble drying or cooking with one large ring will also use up about one kWh each.

And for all of the tea-drinkers out there who have the kettle in a constant state of boiling, it's important to know that half an hour of kettle use will cost 1 kWh too.

About 6 hours of TV-watching or desktop computer use will also use 1 kWh each.

What is a kilowatt?

A kilowatt simply refers to 1,000 watts. It's a measure of power.

A kilowatt-hour, on the other hand, measures usage of 1,000 watts of energy in the space of one hour. It's a measure of consumption.

How are my gas and electricity bills calculated?

When it comes time for your gas and electricity suppliers to calculate your bill, they look at how many kWhs you have consumed during the billing cycle, multiply that number by their unit rate, add in taxes and standing charges and voila, there's the amount you have to pay.

It's important to note that gas and electricity suppliers often estimate the number of kWhs you have used, so it's important to regularly provide up to date meter readings to ensure that you're only billed for what you used.

You'll know that your bill has been estimated by the big 'E' that appears on your bill. 

If you think that your supplier's estimate is higher than your actual consumption, you should provide them with a fresh meter reading and request that your bill is amended.

How can I monitor my usage?

We know that you’re not going to count every minute of usage for every electrical appliance in your house. Thankfully, you can get a great little gadget to do this for you. An Owl electricity monitor will cost you about €50 and, if used correctly, will pay for itself in no time.

We hope this guide helps you get a good understanding of how your bills are calculated and which appliances and activities may be costing you the most. If you aren't happy with the rates you’re paying, we are here to help you find a better deal and switch to a new supplier on our Compare Electricity Prices page.