How do I know if my smart meter is broken?

More than four millions smart meters in Great Britain were not working at the end of 2023, according to government data.

Faulty meters can mean customers rely on estimated bills, with some paying too much and struggling to get their money back.

Smart meters measure how much gas and electricity you use. You get one meter for each energy supply.

According to the Energy Saving Trust, this means you will be billed accurately for the energy you've used.

Smart meters usually come with an in-home display, which can help you track how much energy you're using.

Smart meters don't use your wifi.

Instead, they include a communications hub which connects the smart meter to the in-home display and a secure national smart meter network.

This enables communications between smart meters and all energy suppliers, says Ofgem.

Some earlier smart meters use the 3G network instead.

This means they were not operating in "smart mode" and sending readings to suppliers.

However, Martin Lewis, from MoneySavingExpert, told the BBC Radio 4 PM programme that meters with other problems - such as those sending the wrong readings, or a fault with the in-home display - should be included.

This would mean that about one in five smart meters don't work, he said.

Energy UK, the trade association for the energy industry, says suppliers must replace faulty meters.

Unusual bills, sometimes caused by connectivity issues, and a blank screen on the meter can be signs it is not working correctly.

Your bill will also contain information that could help you find out.

If they are marked with an "e", they're estimated readings, says Citizens Advice.

You can also use its smart checker tool to see if there is a problem between the meter and the central network.

You should contact your supplier - they should help you fix your meter.

Customers who are concerned about paying their bill should contact their supplier, which is required to offer tailored repayment plans and, where appropriate, payment holidays, Ofgem said.

Although it is free, you may have to pay your supplier for organising it if your meter is found to be working correctly.

The government says this was the case for the vast majority of meters tested in 2021.

Meters needs to be replaced every 10 to 20 years and most suppliers no longer install traditional ones.

However, it is not compulsory to have a smart meter unless your current meter is faulty or at the end of its working life, says Ofgem.

You can therefore choose not to accept an offer to have one fitted.