Your Gas Meter: How Does it Work?


If there’s one thing that no energy consumer can abide, it’s inaccurate billing. Fortunately, our energy meters keep track of the energy we use. As long as we report regular meter readings (or install smart meters), we can be assured of fair and accurate bills that really reflect our usage. But what do gas meters do? How do gas meters work? How do you know your gas meter from your electricity meter? And how do you read your gas meter to ensure that your gas bills are accurate. We’ll endeavour to answer all of your questions about gas meters in this post.
Last update: November 2022

What is a gas meter? Why is it important?

A gas meter is a device that calculates how much gas your household is using. Most household gas meters are bellows / diaphragm meters that use the principle of positive displacement to measure the speed and volume of the gas pumped into your home.

Your gas meter is important because it helps to ensure that your gas bills are accurate. Report your meter readings once every quarter (or once a month if you are able) and you can be assured of fair and accurate billing rather than being billed for your estimated usage.

How does your gas meter work?

While there are many different kinds of gas meters such as rotary, turbine and ultrasonic flow meters, most domestic and commercial gas meters use the same bellows / diaphragm mechanism.

Inside the meter, there are chambers formed by movable diaphragms that alternately fill and expel the gas that flows through them. As the diaphragms expand and contract, a system of cranks and levers use this motion to drive a crankshaft.

This in turn drives a counter mechanism like an odometer that logs usage. Alternatively, it can be used to create electrical pulses that are calculated by a flow computer.

What are the different types of gas meter? What do they look like?

Almost all domestic gas meters use diaphragms, but they will look different on the outside depending on the interface. Different meter types include:

  • Standard credit meters- These have a simple mechanical display with 5 black numbers.
  • Digital credit meters- These have a digital display rather than a mechanical display. You may need to press a button to see the reading.
  • Dial meters- These are less common and a little trickier to read. They have a clock-like interface.
  • Prepay meters- Prepay meters can have either mechanical or digital displays but will use a key fob, card or token to add credit.
  • Smart meters- Finally, smart gas meters have electronic displays so you can track your usage. However, you don’t need to report your readings to your supplier, as the meter feeds the supplier usage data constantly to ensure accurate billing.

Gas Meters

How is a gas meter connected?

If you want to replace an existing meter (for example, changing from a prepay meter to a credit meter), this can be done by your energy supplier.

If you need to connect a new meter to the national gas grid or alter the location of your meter, however, you need to contact your local gas transporter. These are the companies responsible for managing, maintaining and upgrading the gas supply and network of pipes in your area. You can find out who your local transporter is by visiting the Energy Networks Association’s website.

How much does it cost to put a gas meter in?

If you’re installing or moving a new smart meter in your property, your supplier will usually do this free of charge. This is because the government is working with energy suppliers to make smart meters available to new UK homes by 2025. Replacing an existing meter will likely cost anywhere between £120 and £200 depending on your supplier. However, some of the larger suppliers may replace your meter for free if you want to convert to a different kind of meter.

How to read a gas meter?

Reading a mechanical or digital meter is fairly straight forward. Just report the numbers on the meter from left to right. On a mechanical meter, there may be some red numbers alongside the black numbers. These do not need to be reported. Dial meters are a little more complicated as the needle may be positioned between numbers on the dial. In this case, always report the last number that the needle has passed.

When in doubt, take a photo of your meter on your smart phone and send this to your supplier.
They will be able to log the reading for you.

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What should a gas meter reading look like?

A gas meter reading will usually be 4-5 digits long. There may be a red mark with 2-3 digits after it to the right of the meter reading. These can be disregarded.

Where is my gas meter’s serial number?

Your gas meter has a meter ID or ‘MSN’. This will usually appear on your energy bill. You can also see it on the meter near the barcode. It contains a mix of both letters and numbers. Contact your local gas transporter if you’re unsure of your gas meter number.

How do I calculate my gas bill from a meter reading?

If you want to find out what to expect in your next bill, you can calculate your bill using your meter reading.

  • The first thing to do is work out what you’ve used since your last meter read. To do this, simply deduct the number on your last meter reading from your current meter reading.
  • Your meter will display your usage in cubic meters. So the next thing you’ll need to do is convert this into kilowatt hours (kWh). To do this multiply the number of cubic meters of gas by 11.1868.
  • If your meter uses imperial measurements (cubic feet), multiply the reading by 31.6586 to get the same amount in kWh.
  • Now you have the right kWh value, multiply this by the unit rate for gas. This is usually around 2-3p per kWh. You’ll also need to multiply your gas standing charge by the number of days it’s been since your last bill.
  • Put these two figures together, and you’ll have a figure for your gas spending.

How to top up your prepay gas meter

If your home uses a prepay gas meter, you’ll need to learn how to top up to ensure a constant supply of gas to your home. Most meters of this kind come with a card or key. You can take this to any UK store with the PayPoint logo. Click Here to find the nearest one to you.

You can also top up by calling your energy supplier, logging into your online account, or using your supplier’s mobile app if they have one.

What if my gas meter’s display is blank?

If your prepay gas meter is blank, try taking your card or key out, waiting a few seconds and reinserting it. If this doesn’t work, try pressing the buttons to see if the display comes up (most meters have a red and a blue button). If this doesn’t work, there may be a fault with your meter. Contact your gas supplier as soon as you can and they will be able to investigate.

If the meter is faulty, they should replace it free of charge.

We can help you get the best gas rates

Accurate meter readings are very important in ensuring a fair gas bill. Even more important, however, is knowing that you’re with the best supplier and tariff for your needs. That’s where we come in! We can scour the market to find you the best gas supplier on the market for your needs and usage. We’ll even manage your switch from end-to-end so that we can bring you cheaper gas quickly and completely hassle-free.

Would you like to know more about energy meters? Great!
Check out these related articles:

  1. Set up gas and electricity
  2. Sign up for gas and electricity
  3. Gas and electricity quotes
  4. Electrical safety

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Is there such a thing as smart gas meters?

Yes. Smart meters are available for gas as well as electricity. These are white with an LCD display. If you have a smart meter in your home, you don’t need to take meter readings as your usage is recorded automatically.

Where is a gas meter normally located?

If you are in a house, your gas meter will usually be outside the house, at the side or around the back. If you are in an apartment building, your gas meter will likely be indoors in a dedicated cupboard. 

Who is responsible for your gas meter?

Your gas supplier is responsible for managing and maintaining your meter, and the costs associated with this are folded into your gas bills. 

How many kWh is a m3 of gas?

If you want to get a clear idea of your gas usage, you may want to m3 (cubic meters) into kilowatt hours (kWh). Simply multiply the amount of cubic meters of gas by 11.1868 to get the equivalent amount in kWh. 

Updated on 29 Jan, 2024

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