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A commercial gas meter measures the volume of gas flowing into your business premises, and your supplier converts that volume into the kWh you see on your bill. What most owners never learn is that the meter itself carries a cost: your meter size directly sets your standing charge, so a business on an oversized meter pays for capacity it never uses, every single day. That makes your gas meter a billing decision, not just a piece of pipework.
This guide covers the types of gas meters used in UK businesses, the U6 to U160 sizing system and what each size means, what installation genuinely costs, and the situations where changing or even removing your meter saves money.
Ready to act rather than read? If you suspect your meter or your rate is costing you more than it should, compare business gas prices with our team and we will review your metering alongside your contract.
What is a commercial gas meter?
A commercial gas meter, often called a business gas meter, records the volume of gas your premises draw from the network, measured in cubic metres or cubic feet depending on the meter's age. Your supplier then converts that volume to kilowatt hours using the gas's energy content, which is why your bill shows kWh even though the meter counts volume.
Physically, a small commercial meter is often identical to a domestic one. The difference is how the supply is registered and billed: your premises has an MPRN, the unique reference number tying your address to the gas network, and it is the supply registration rather than the hardware that makes a meter commercial. Larger businesses move into bigger meter classes, which is where the real differences begin.
What are the types of gas meters used by UK businesses?
Five types of gas meters cover almost every commercial premises in Britain.
Gas meter type
How it measures
Best suited to
Metric gas meter
Cubic metres (m³), five digits
Most premises; the modern standard
Imperial gas meter
Cubic feet (ft³), four digits
Older premises awaiting upgrade
Smart gas meter
Metric, sends reads automatically
Small and medium businesses
AMR meter
Automated remote readings
Larger multi site businesses
Prepayment meter
Credit loaded in advance
Short term tenancies; best avoided
Metric gas meters
The modern standard. A metric gas meter measures in cubic metres and shows five digits before the decimal point. If your premises was fitted out or re-metered in the last two decades, this is almost certainly what you have.
Imperial gas meters
Older meters that measure in cubic feet, showing four digits. They work perfectly well, but there is a billing trap: imperial readings must be converted to metric before the kWh calculation, and a supplier applying the wrong conversion produces a wildly wrong bill. If your bills swing oddly and you have a four digit meter, check the conversion first.
Smart gas meters
The replacement for both, in smaller premises. A smart gas meter sends readings to your supplier automatically, which ends estimated billing and gives you consumption data worth acting on. Suppliers fund the upgrade as part of the national rollout, so for most small businesses the sensible answer to a smart meter offer is yes.
AMR meters
Automated Meter Reading units serve larger sites and multi site portfolios, transmitting reads remotely on a schedule. They predate smart meters and remain common on bigger commercial supplies where consumption data feeds energy management rather than just billing.
Prepayment gas meters
Pay as you go meters requiring credit before gas flows. They exist mainly to manage supplier credit risk in short term tenancies or after account debt, and their unit rates run higher than credit meters. If your business is on one, moving off it is usually the single quickest saving available.
Commercial gas meter sizes explained: U6 to U160
UK commercial gas meters are sized by the U rating, where the number is the meter's maximum flow capacity in cubic metres per hour. A U6 passes up to 6 m³ of gas an hour, a U40 up to 40, and so on. Converted to energy, each m³ per hour supports roughly 10.8 kW of gas demand.
Meter size
Maximum flow
Approximate maximum demand
Typical premises
U6
6 m³ per hour
Up to ~65 kW
Shops, cafes, small offices; also the standard domestic size
U16
16 m³ per hour
~66 to 173 kW
Restaurants, larger offices, small hotels
U25
25 m³ per hour
~174 to 271 kW
Hotels, schools, mid size commercial kitchens
U40
40 m³ per hour
~272 to 434 kW
Large hospitality, leisure centres, light industrial
U65
65 m³ per hour
~435 to 704 kW
Industrial units, large commercial buildings
U100
100 m³ per hour
~705 to 1,083 kW
Manufacturing, large industrial sites
U160
160 m³ per hour
1,084 to 1,733 kW
Heavy industrial and process sites
Figures are approximate and cross checked against meter manufacturer specifications; your network operator confirms exact sizing for any installation. Three details worth knowing: most small businesses run a U6 and never need more, a U16 is generally the minimum for a commercial kitchen, and engineers size meters on the diversified peak demand of all your gas appliances running together, not the sum of their nameplate ratings, because equipment rarely runs at full load simultaneously. Sites using above roughly 732,000 kWh a year typically move beyond diaphragm meters altogether, onto daily metered supplies with rotary metering.
Physical gas meter dimensions grow with capacity too: a U6 is a compact wall mounted box, a U16 or U25 needs a larger cupboard or external housing, and U65 and above are substantial floor standing units on a plinth. If a commercial gas meter upgrade to a larger size is on the cards, check the space and ventilation around the meter position before the engineer visit, because relocating pipework is where the cost climbs.
The practical takeaway: bigger meters carry bigger standing charges. A business that installed a U40 for equipment it later removed, or inherited an oversized meter with the premises, is paying elevated daily charges for headroom it never touches. We see this regularly on inherited leases, and a meter downsize is one of the few changes that cuts your bill every day for the rest of the contract. It is always worth checking before a business gas renewal.
How does your gas meter affect your business gas bills?
It sets your standing charge. Meter size feeds directly into the fixed daily charges on your bill, as the sizing table shows. Sites supplied through an Independent Gas Transporter pay more again, whatever the meter.
It converts volume into the kWh you pay for. Suppliers convert your reading using a formula set by the Gas (Calculation of Thermal Energy) Regulations: cubic metres, multiplied by a volume correction factor of 1.02264, multiplied by the calorific value of the gas, divided by 3.6. GOV.UK's official guidance confirms transporters must keep the calorific value between 38 and 41 megajoules per m³, and the exact value used for your bill is printed on it. Imperial readings are converted to metric first by multiplying by 2.83. You do not need to memorise any of this, but knowing the formula exists means you can check a suspicious bill instead of trusting it.
It decides whether your bills are real or estimated. Old meters with no communications mean estimated bills, and estimates drift until a painful correction arrives. Smart and AMR meters end that, and the consumption data they produce is exactly what energy monitoring turns into savings.
When does a business need a new gas meter?
Upgrading to a smart meter as part of the supplier funded rollout
Upsizing because new equipment, such as a commercial kitchen fit out, pushes demand beyond the current meter's capacity
Downsizing an oversized meter to cut standing charges after demand has fallen
Replacing a faulty, damaged or end of life meter, which is the supplier's responsibility
Relocating the meter during a refit or redevelopment
A premises with no gas connection at all needs a new connection through the network operator first, which is a longer and separately priced process than a meter swap.
How much does commercial gas meter installation cost?
Gas work is regulated, so every commercial gas meter installation must be carried out by a Gas Safe registered engineer. What it costs depends entirely on which situation you are in.
Free: smart meter upgrades under the national rollout, and replacements for faulty or end of life meters, are supplier funded
Often free: a standard meter installation agreed as part of signing a new fixed contract with a supplier
A few hundred pounds: a straightforward chargeable swap or relocation on an existing supply
Into the thousands: upsizing that requires pipework upgrades, or larger industrial installations with bespoke metering
The process itself is routine: a site assessment, then on the day the supply is isolated, the meter exchanged, the supply purged and leak tested with a manometer, and a calibration check completed. Straightforward swaps take an hour or two. Plan it for a quiet trading period, because the gas is off while the work happens.
Should your business remove its gas meter entirely?
Here is the question almost nobody asks, and it is worth real money to a growing number of businesses. If you have electrified, moved to heat pumps or induction catering, or simply stopped using gas, your meter is still costing you the standing charge every day. At 25p to 45p a day, an unused gas supply quietly burns £90 to £165 a year, indefinitely, for nothing.
A Gas Safe engineer can remove the meter and cap or disconnect the supply, which ends the standing charges permanently. Keep the supply if there is a realistic chance you will want gas again, because reconnection costs more than removal. But paying daily charges for a fuel you no longer use is one of the most common silent leaks we find in utility reviews.
Compare business gas rates with Green Light
At Green Light Consultancy Group, metering questions and contract questions get answered together, because they are the same question: what should this premises be paying for gas? We check whether your meter size matches your actual demand, whether your reads are real or estimated, and whether your unit rate and standing charge stand up against the current business gas rates for your size. Where a downsize, an upgrade or a full disconnection would save you money, we tell you plainly, and where your setup is already right, we tell you that too.
It depends on your peak gas demand in kW. Most small businesses run a U6, which supports up to roughly 65 kW. A commercial kitchen or hotel typically needs a U16 or U25, and industrial sites go larger. Your network operator confirms sizing from your peak hourly demand before any installation.
What is a U6 gas meter?
The standard small commercial and domestic gas meter, rated for a maximum flow of 6 cubic metres of gas per hour, supporting up to roughly 65 kW of demand. If your business is a shop, cafe or small office, you almost certainly have one.
How do I tell if my gas meter is imperial or metric?
Count the digits and check the units. A metric gas meter shows five digits and measures in m³. An imperial meter shows four digits and measures in ft³. The unit is printed on the meter face next to the display.
Is my gas meter domestic or commercial?
Often the hardware is identical. What makes a supply commercial is how it is registered and billed, not the meter itself. Your supplier can confirm your supply status from your MPRN or account details.
How much does a commercial gas meter installation cost?
Anywhere from free to several thousand pounds. Smart upgrades and faulty meter replacements are supplier funded, standard swaps on a new contract are often free, chargeable swaps run a few hundred pounds, and upsizing with pipework changes costs more. Always get the cost confirmed in writing before work is booked.
Can downsizing my gas meter reduce my bills?
Yes, if your meter is genuinely oversized for your demand. Standing charges scale with meter size, so a business running U6 level demand through a U16 or U25 meter pays elevated daily charges for nothing. A demand check against the sizing bands answers it quickly.
What is an MPRN number?
Your Meter Point Reference Number, the unique identifier linking your address to the gas network. It appears on your gas bill, not on the meter itself, and you need it for switches, installations and connection work.
Do smart gas meters save businesses money?
Not by themselves. They end estimated billing and show you when gas is being used, and the savings come from acting on that data: fixing waste, right sizing the meter and negotiating renewals with real consumption figures.
Switch Business Gas
To find out whether your gas meter and your contract are working for your business or quietly against it, get in touch with the team today.
Is Your Commercial Gas Meter Costing Your Business More Than It Should?
Your gas meter size directly affects your standing charges. Let our experts review your meter, usage and contract to identify potential savings and ensure your business is on the right tariff.
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