Lowering bills, cutting carbon

Back to News

Your guide to smart meters


Chances are, you’ve either got a smart meter, or been asked by your supplier if you want one. But what exactly are they, how do they work, and why do some people not want them? Find out in our guide to smart meters.

In this guide to smart meters

What is a smart meter?
Do I have a smart meter?
What are smart meters for?
Do I need to worry about my smart meter?
Do I have to have a smart meter?
I’ve heard people talk about ‘first generation’ and ‘second generation’ smart meters. What’s the difference?
Can I switch supplier if I have a smart meter?
Will I have to have my smart meter replaced if I switch supplier?
Do I have to pay to have a smart meter installed?

What is a smart meter?

Very simply, a smart meter helps you – and your supplier – to better understand how much energy you’re using, and when you’re using it. That should mean you get more accurate bills, and that you’re better able to spot ways in which you can lower your energy use, which helps lower carbon emissions and saves you money.

There are two parts to a smart meter. The main unit replaces the old-fashioned meter (often found in a cupboard or under the stairs). This part records how much electricity and/or gas your household or business consumes. The smart meter then sends this information to your energy supplier so they can make sure they’re charging you accurately.

The main unit of a smart meter replaces the old meter (often found in a cupboard or under the stairs)

The second part of the smart meter is a digital display that you can position wherever you like in your home, and which tells you how much energy you’re using at any given time – as well as how much you’re spending. 

The smart meter's in home display provides you with information about how much energy you're using, and how much it costs

Do I have a smart meter?

Smart meters are normally easy to spot – the part that replaces your old meter usually has a white face with a digital display. Other indications that you’ve got a smart meter include:

  • If you pay by direct debit or on receipt of a bill, and you’re not asked to send meter readings to your supplier (because the smart reader sends them automatically)
  • If you’re on a pre-payment meter and can top-up online

If you’re not sure, the best thing to do if you’re not sure is to call up your energy supplier and ask them or drop us a line and we’ll find out for you.

What are smart meters for?

Here’s what’s great about smart meters:

Smart meters help you understand how you’re using energy

By making energy use more visible, smart meters can help us spot when we’re going over budget, or when we may need to adjust our heating. That means lower bills and lower carbon emissions.

Smart meters mean smarter tariffs

Because smart meters record how much energy you’re using over very short periods of time (usually half hour blocks), we’ll eventually be able to use them to find energy tariffs to match our habits. If you have storage heaters or an electric vehicle, for instance, you might be able to find tariffs that offer very cheap electricity during the hours you typically use more power, helping to lower your bills.

Smart meters enable smarter homes

Because your smart meter connects with your supplier, if you’re on a tariff that offers cheaper power at a particular time of day, your smart meter will be able to activate certain equipment – such as an electric car charge point – when cheaper electricity kicks in.

Smart meters mean more accurate bills

Do you ever get fed up with building up a huge surplus in an energy account before a supplier adjusts your direct debits? Being able to understand your energy use hour by hour will mean suppliers can ensure you’re being billed more accurately (this may also mean your supplier makes small adjustments to your direct debits more often, but remember, a supplier can ultimately only ever charge you for the energy you actually use).

Smart meters allow you to sell energy you generate or store back to the National Grid

If you have solar panels, you can now sell your surplus electricity back to the Grid. You can even shop around for which supplier will offer you the best deal for this, although this market is still fairly under-developed. Either way, you’ll usually need a second generation (SMETS 2) smart meter to do this.

Do I need to worry about having a smart meter?

You may have heard some people express concern about the installation of smart meters. Worries normally focus on two areas:

  1. Concerns about radio waves
  2. Concerns about privacy

Let’s look at each of those in turn…

Concerns about radio waves from smart meters

Some campaigners fear that the radio waves used by smart meters to send data to suppliers may have negative health implications. Public Health England – the organisation that provides the government with evidence to inform policies around health – has conducted extensive research on this issue. They found that:

Exposure to radio waves from smart meters is well below the guidelines set by the International Commission on Non-Ionizing Radiation Protection (ICNIRP)… Exposure to the radio waves produced by smart meters is likely to be much lower than that from other everyday devices such as mobile phones and wifi equipment… Public Health England considers exposure to radio waves does not provide a basis to decline having a smart meter.

If you’d like to read more about this issue, this post by the American Cancer Society is a good place to start.

Concerns about privacy

The other principal criticism of smart meters concerns privacy. That’s because your energy use data can reveal a lot about you – including whether you’re even at home or not. Campaigners worry both that smart meters could be hacked illegally, and that data collected legally could be used by companies to sell or market other products. Here’s what Smart Energy GB, the UK government’s delivery body for the smart meter rollout, says on the first of these topics:

Security has been at the heart of the whole smart meter rollout programme from its very inception, and the system has been specifically designed to prevent hacking. Smart meters do not use the internet, and they have their own closed, dedicated communications system. Smart meters have been designed with top cyber security experts, including the government and GCHQ, to ensure that security best practice has been incorporated at every stage.

When it comes to the use of your data for commercial purposes, the risks are mitigated in two ways:

  1. First, the type of data stored on, and transmitted by a smart meter is closely regulated. Smart meters don’t, for example, store financial information. They only store data about what energy is used, when.
  2. Second, what happens to that data is controlled by you. Unless you expressly give permission, the data cannot be shared with anyone else.

Do I have to have a smart meter?

The short answer is no. The government is asking all energy suppliers to offer a smart meter installation to all small businesses and homes in the UK, but right now they are not a legal requirement, so you don’t have to have one. 

I’ve heard people talk about ‘first generation’ and ‘second generation’ smart meters. What’s the difference?

Energy suppliers began to install the first generation of smart meters in 2013. These meters complied with a common set of standards known as the ‘Smart Metering Equipment Technical Specifications 1’, more commonly known as ‘SMETS1’. Unfortunately, if you had one of these meters and changed supplier, the meter would stop sending its automatic readings (although you could still read the meter manually and send the readings to the new supplier).

That’s why most suppliers are now installing the second, ‘SMETS2’ generation of smart meters. These can be read no matter which supplier you are with, so if you switch, you won’t need to go back to providing manual meter readings.

Don’t worry if you have a SMETS1 meter though – the government is gradually upgrading these remotely so they function like second generation meters.

How can I tell which type of smart meter I have?

The rollout of the second smart meters began in 2018, so if yours was installed before that then it’s probably a SMETS1, although some suppliers carried on installing the SMETS1 after 2018 to clear their stock, so this isn’t guaranteed. To be absolutely sure, ask us, or call your supplier and ask them.

I have a SMETS1 meter – can I switch to a SMETS2 meter?

This is up to your supplier. Unless you need a SMETS2 meter to take advantage of a smart tariff, They’re likely to ask you to wait until your SMETS1 meter is upgraded – or charge you to replace it.

Can I switch supplier if I have a smart meter?

Absolutely. If you pay a supplier for your energy bills, then you have the right to choose your supplier (and the freedom to use that choice to support the transition to a greener energy system). If you have an older type of smart meter, you may have to go back to providing manual meter readings for a time (usually a small price to pay relative to the potential savings!).

Will I have to have my smart meter replaced if I switch supplier?

No. Although your current supplier pays for the installation of the smart meter, they won’t tear it out if you switch. Instead, responsibility for controlling the meter (and reading the data from it) will pass to your new supplier.

Do I have to pay to have a smart meter installed?

No. There’s no direct cost to you – the smart meter rollout is paid for by the suppliers. In practice, these costs are likely to be passed on to consumers in the rates we pay for our energy.


If there’s something not covered in this guide to smart meters that you’d like to know more about, drop us a line at help@bigcleanswitch.org and we’ll make sure it’s added.