SMETS1 vs SMETS2 | Everything You Need to Know

Quick summary: SMETS1 vs SMETS2 mainly comes down to how the meter communicates with energy suppliers, with SMETS2 meters designed to stay fully smart when you switch providers.

In the world of smart meters, there are two primary formats: SMETS1 and SMETS2. Both types record your energy use and automatically send readings to your supplier. The biggest difference is the communications system behind them. Earlier SMETS1 meters were introduced before the national smart meter network was fully established, while SMETS2 meters were designed to work through that network from the outset.

That difference mattered particularly when households and businesses changed energy suppliers. Many older SMETS1 meters could lose their smart functions after a switch, leaving customers to submit readings manually again. Today, the position is much better because the vast majority of eligible SMETS1 meters have been migrated onto the national network.

What are smart meters?

Smart meters are digital gas and electricity meters that record exactly how much energy you use and can send that information directly to your energy supplier. The term SMETS refers to the technical standards used for smart metering equipment. The two generations most business settings and households will come across are SMETS1 and SMETS2.

With a traditional meter, somebody has to read the figures on the meter itself. That might mean taking a reading yourself and submitting it online or through an app. If no reading is supplied, your energy company may have to estimate how much you have used, which can result in estimated billing.

How do smart meters work?

A smart meter removes much of that admin. Once it is working in smart mode, readings can be sent automatically at agreed intervals, helping your supplier produce bills based on actual consumption rather than estimates.

What is a SMETS1 meter?

SMETS1 stands for Smart Metering Equipment Technical Specifications first generation. These were the first generation of smart meters installed at scale in Great Britain. They were introduced before the Data Communications Company, or DCC, national smart meter network became fully available. As a result, different energy suppliers originally used different communications arrangements to receive data from SMETS1 meters.

The problem was interoperability. A SMETS1 meter that communicated perfectly with the supplier that installed it might not initially have been able to communicate in the same way with a new supplier.

How SMETS1 meters work

A SMETS1 meter records your energy consumption electronically and uses communications technology to pass information to your supplier.

• Originally, these meters often communicated through systems arranged by individual suppliers or their chosen smart meter service providers. That meant communication routes weren’t necessarily shared by energy companies.
• If you stayed with the same supplier, the meter could continue sending readings normally. 
• If you switched to a supplier that couldn’t communicate with that particular meter, the meter would keep measuring your gas or electricity use, but its smart features may stop working.
• This is what people mean when they say a smart meter has gone into “traditional mode” or “dumb mode”. It still works as a meter, but you may need to submit readings manually.

That situation has improved significantly because millions of SMETS1 meters are now enrolled on the DCC network, allowing them to operate more like SMETS2 meters when customers change suppliers.

What is a SMETS2 meter?

SMETS2 stands for Smart Metering Equipment Technical Specifications second generation. SMETS2 meters were developed to address some limitations of the first generation.

The important difference is that SMETS2 meters were designed to communicate through the DCC’s national smart meter network rather than relying on supplier-specific arrangements. This creates a common communications infrastructure that authorised energy suppliers can use. As a result, changing suppliers should not normally mean losing your meter’s smart functionality.

SMETS2 installations became widespread from 2018 onwards, and they are now the standard generation used for new smart meter installations.

How SMETS2 meters work

Your SMETS2 gas and electricity meters form part of a smart metering system within your property. 

• A communications hub handles information from the meters and connects the installation to the wider DCC network.
• Your supplier can use this secure infrastructure to receive meter readings and perform permitted remote functions. 
• If you switch suppliers, the new supplier can communicate with the same smart metering equipment through the DCC network rather than needing a completely separate system.

SMETS1 vs SMETS2 | What is the difference?

The real difference between SMETS1 and SMETS2 is how those functions are supported behind the scenes.

Communication and connectivity

• SMETS1 meters were introduced before the national DCC infrastructure was available, so their communications were originally handled through several different systems.
• SMETS2 meters were designed specifically to connect through the DCC network.

This difference is much less noticeable than it once was because the vast majority of eligible SMETS1 meters have now been migrated to DCC systems. Once successfully migrated, a SMETS1 meter can gain interoperability it did not necessarily have when first installed.

Switching energy suppliers

Historically, switching suppliers was one of SMETS1 meters’ biggest weaknesses. A customer could change provider only to discover that its meter no longer sent automatic readings. SMETS2 was designed to prevent that problem. Because participating suppliers use the DCC network, the meter should remain smart after a switch.

A successfully migrated SMETS1 meter can also continue operating smartly after switching, so having SMETS1 does not automatically mean you will lose functionality.

Automatic meter readings

Both SMETS1 and SMETS2 meters can send readings automatically while operating in smart mode. The difference is reliability across supplier changes. An unmigrated SMETS1 meter may be unable to communicate with a new supplier, while SMETS2 meters and migrated SMETS1 meters are designed to support continued communication through the DCC network.

Compatibility and interoperability

Interoperability simply means that the meter can work with different energy suppliers rather than being effectively restricted to the company that installed it. The SMETS2 model builds this in. For SMETS1 meters, interoperability has largely been achieved by enrolling compatible meters onto the DCC network.

Remote meter management

Because SMETS2 meters use the national network, suppliers have a consistent route for communicating with compatible equipment. Suppliers can also manage migrated SMETS1 meters through DCC systems, although differences may remain between individual meter models.

How to tell which smart meter you have

You cannot always identify a SMETS1 or SMETS2 meter just by looking at the front of it. Different manufacturers produce different designs, and two meters that look similar may belong to different generations.

• The easiest starting point is the installation date. If your smart meter was installed before 2018, it is more likely to be SMETS1. A later installation date makes it more likely to be SMETS2, although the date alone is not definitive.
• You can also contact your energy supplier and ask which generation is registered at your property.
• Another useful clue is what happens when you switch supplier. If an older meter has continued sending readings automatically after a change, it may be a SMETS2 or a SMETS1 meter that has already been enrolled onto the DCC network.

Ultimately, contacting your supplier is the best way to confirm the meter type and whether it is currently communicating in smart mode.

Why SMETS2 matters when you switch supplier

Retaining smart functionality after switching

A SMETS2 meter is designed so that a new supplier can communicate with it through the DCC network. That means you shouldn’t need a replacement meter just because you move to another provider. Automatic readings, remote communications and other supported smart functions can continue without the meter being tied to the original installer.

The same principle now applies to successfully migrated SMETS1 meters.

Avoiding a return to estimated billing

When a smart meter stops communicating, your supplier may ask you to submit manual readings. If you don’t provide those readings, bills may be based on estimates, which can lead to overpriced or otherwise inaccurate bills. Smart connectivity makes it easier for your supplier to receive regular readings and bill you based on recorded consumption.

Keeping in-home display data

Your in-home display communicates with the smart metering equipment in your home, so it may continue showing usage information even if there is a temporary problem sending data to your supplier. After a supplier switch, tariff information displayed on the IHD may take time to update. If figures appear incorrect or the display stops updating, contact your supplier before assuming the meter itself has failed.

What happens to SMETS1 meters now?

Migration to the DCC network

The large-scale SMETS1 migration programme has now moved the vast majority of eligible meters onto the DCC network. For consumers, migration generally happens remotely rather than through a visit to the property. Once successfully enrolled, a compatible SMETS1 meter can retain smart functions across supplier changes, much like a SMETS2 installation.

If migration is not possible, your supplier may need to arrange replacement equipment.

Meters still operating in traditional mode

Some smart meters may still operate in traditional mode because they are not communicating correctly. If yours does, it does not mean it has stopped measuring energy. You may simply need to take readings manually while the communication issue is investigated or a replacement meter is fitted.

Government policy from 2026 strengthens expectations that suppliers take reasonable steps to return meters from traditional mode to smart operation promptly, with a 90-day backstop from when the supplier becomes aware of the problem.

Impact of 2G and 3G network switch-off

The UK is gradually retiring older mobile communications technology, which matters because some smart meter communications equipment uses 2G or 3G services.

Government policy requires suppliers to take reasonable steps to replace smart metering assets before the relevant communications services end. Current plans require communications hubs that depend on 2G or 3G in affected regions to move to equipment supporting newer connectivity by the end of 2033.

If your installation is affected, your energy supplier should manage the necessary upgrade rather than expecting you to solve the communications change yourself.

Do you need to upgrade to SMETS2?

Not necessarily. An upgrade becomes more relevant if your meter cannot be enrolled, repeatedly loses smart functionality, has a communications problem that cannot be resolved or needs replacing as part of wider network modernisation.

• If you have a SMETS1 meter that is communicating properly through the DCC network, however, being first generation does not automatically make it obsolete.
• A working SMETS1 meter can still send readings automatically and retain many of the practical benefits people associate with newer smart meters. 
• Replacing perfectly functional equipment simply because the label says SMETS1 is therefore unlikely to be necessary.
• What matters most is whether the meter communicates properly and provides the services it is supposed to.

How to request a smart meter upgrade

1. If you believe your smart meter is no longer working properly, contact your current energy supplier first.
2. Explain what is happening. For example, tell them if automatic readings have stopped, your account is showing estimated readings, your in-home display isn’t updating, or smart functionality disappeared after you changed suppliers.
3. Ask the supplier to confirm whether your meter is SMETS1 or SMETS2, whether a SMETS1 meter has been enrolled onto the DCC network, and whether there is an active communications fault.
4. If the issue can be corrected remotely, you may not need a replacement. 
5. If your equipment is incompatible, cannot be migrated or needs changing for technical reasons, the supplier can explain the next steps and arrange an appointment where appropriate.

Conclusion

Both generations measure energy use and support automatic meter readings. The main difference is that SMETS1 arrived before Great Britain had a single national smart meter communications network, while SMETS2 was designed around that network from the start.

That meant early SMETS1 meters could lose smart functionality when customers changed energy supplier. However, the picture has changed considerably. The vast majority of eligible SMETS1 meters have now been migrated onto DCC systems, giving them much better interoperability. 

If it has dropped into traditional mode or stopped communicating, speak to your supplier. They can confirm whether it can be restored remotely or whether it needs an equipment upgrade.

For most customers, therefore, the important thing is not simply which generation of smart meter is sitting in the cupboard. What matters is whether it is connected, sending accurate readings, and working as intended.

For more insights into all sorts of different energy topics, make sure to visit the D-ENERGi blog today. Our resource bank is packed with content just like this for anyone looking to better understand the energy market. 

Frequently Asked Questions

What does SMETS stand for?

SMETS stands for Smart Metering Equipment Technical Specifications. SMETS1 refers to first-generation smart metering equipment, while SMETS2 refers to the second-generation specification.

What is the main difference between SMETS1 and SMETS2?

The main difference is the way the meters communicate. SMETS1 meters were originally installed using several communication arrangements, while SMETS2 meters were designed to use the DCC national smart meter network. Many SMETS1 meters have since been migrated onto that network.

Will my SMETS1 meter stop working if I switch supplier?

Not necessarily. A SMETS1 meter successfully migrated to the DCC network should retain its smart functionality when you switch suppliers. If an older meter is not communicating with your new supplier, it will still record energy use, but you may need to submit readings manually while the issue is resolved.

How do I know if I have a SMETS1 or SMETS2 meter?

The installation date can give you a clue, but it is not a guaranteed way to identify the meter. Your energy supplier can confirm which generation is installed and whether the meter is operating in smart mode.

Is SMETS2 compulsory for new smart meter installations?

SMETS2 is the standard approach used for new smart meter installations. However, an existing SMETS1 meter does not automatically need replacing simply because it is older. If it has been migrated to the DCC network and continues working correctly, it can remain in service.