SMETS1 vs SMETS2 Smart Meters UK 2026: What's the Difference and Which Should You Have?

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*New to smart meters in general? Start with our Smart Meter Guide UK for the basics, then come back here for the technical comparison.*

SMETS1 vs SMETS2: the short answer

If you only read one paragraph: SMETS2 is the current UK smart meter standard, in every install since late 2018 and the only generation that keeps working properly when you switch supplier. SMETS1 was the first generation, rolled out from 2012 to 2018, and roughly 4 million of them are still in "dumb" mode in 2026 — sending estimated readings instead of automatic ones. Most SMETS1 meters are being migrated onto the same national network (the DCC) that SMETS2 uses, but if yours is causing problems today, you can ask your supplier for a free SMETS2 replacement under the Ofgem rules.

This guide explains exactly what changed between the two generations, how to tell which one is sitting in your meter cupboard, and when it is worth pushing your supplier for an upgrade.

What does SMETS actually stand for?

SMETS is the Smart Metering Equipment Technical Specification — the engineering standard the UK government wrote to make sure every smart meter sold in Great Britain behaves the same way regardless of which supplier or manufacturer made it. There are two generations published so far: SMETS1 (the original 2012 spec) and SMETS2 (the revised 2018 spec). Every smart meter installed in a UK home is either one or the other.

A separate spec for the in-home display (IHD), called SMETS2 IHD, sets out how the small kitchen screen talks to the meter. That part of the standard has held up well, which is why a SMETS2 IHD from any supplier will usually pair with any SMETS2 meter.

SMETS1 vs SMETS2 in one paragraph

SMETS1 meters were the rollout's pioneers. They were installed from 2012 onwards by individual suppliers, each running their own back-end network. When you switched supplier the meter often lost its smart functionality and went back to manual readings — the famous "dumb meter" problem. SMETS2 meters were introduced in late 2018. They connect to a single national communications network called the Data Communications Company (DCC), which is independent of any one supplier. That means a SMETS2 meter keeps working as a smart meter through any number of supplier switches, supports remote tariff updates, and can unlock modern features like time-of-use tariffs and half-hourly export readings for solar.

How to tell whether your smart meter is SMETS1 or SMETS2

There is no SMETS badge on the front of the meter. You have to work it out indirectly. The easiest checks, in order, are:

1. Look at the install date. If your meter was fitted before March 2019, it is almost certainly a SMETS1. If it was fitted after September 2019, it is almost certainly a SMETS2. Anything in between could be either, depending on supplier and region.
2. Ask your supplier. They have it on file. The chat agents at the big six can usually answer in under a minute — say "is my smart meter SMETS1 or SMETS2?" and have your meter point reference number (MPRN/MPAN) ready.
3. Check the model number against the GOV.UK approved list. The model is printed on the meter itself, usually near the LCD display. Common SMETS1 models include Secure Liberty 100, Aclara SGM1416-B and Elster AS300P. Common SMETS2 models include Aclara SGM1456-B, Honeywell A100C, Kaifa MA120 and Landis+Gyr E470.
4. See whether your in-home display keeps working after a supplier switch. If you switched supplier in the last two years and the IHD has been blank or showing dashes ever since, you almost certainly have a SMETS1 meter that has not yet been enrolled into the DCC network. (If yours has gone blank, run through our smart meter problems guide first — half of dark IHDs are battery or range issues, not the meter.)
5. Check the Bright app or a third-party IHD. Apps that use the official DCC consent flow (Hildebrand's Bright app is the obvious one) will refuse to enrol a non-migrated SMETS1 meter. If the app pairs successfully, you are on SMETS2 or a migrated SMETS1.

If you still are not sure after all of that, your supplier is the source of truth. They can also tell you whether your SMETS1 has been migrated to the DCC network.

SMETS1 vs SMETS2: the full comparison

The practical differences for a UK household in 2026, line by line:

• Install years. SMETS1 ran from 2012 to early 2019. SMETS2 has been the default install since late 2018.
• Communications network. SMETS1 originally used proprietary supplier networks. SMETS2 uses the DCC national network from the start.
• Survives a supplier switch? SMETS1 often goes dumb until DCC-migrated. SMETS2 survives every switch.
• Remote tariff updates. SMETS1 is limited and supplier-dependent. SMETS2 supports fast remote tariff pushes.
• Third-party IHDs (Hildebrand Glow etc.). Only work with SMETS1 after DCC migration. Work out of the box with SMETS2.
• Half-hourly export readings for SEG. Patchy on SMETS1, reliable on SMETS2.
• Time-of-use tariffs (Octopus Agile etc.). Sometimes available on a migrated SMETS1, fully supported on SMETS2.
• Prepayment mode switch without engineer visit. Not on SMETS1. Yes on SMETS2.
• Approximate share of UK installs in 2026. About 13 million SMETS1 still in service, about 23 million SMETS2 and growing.
• Government and Ofgem priority. SMETS1 is being migrated or replaced. SMETS2 is the default for all new installs.

A few of these deserve more explanation.

Why SMETS1 meters went "dumb"

When a SMETS1 meter was installed by, say, British Gas, it talked to British Gas's own back-end system. If you switched to Octopus, Octopus did not necessarily have access to that back-end, so the meter would keep recording usage locally but stop sending it. The IHD would go blank, your bills would revert to estimates, and you would be back to taking manual readings.

The fix is the SMETS1 enrolment programme, run by the DCC since 2018. It migrates SMETS1 meters from their original supplier network onto the same national DCC infrastructure that SMETS2 uses, without an engineer visit. Once migrated, a SMETS1 meter behaves much more like a SMETS2 — it survives supplier switches, accepts remote tariff updates, and works with third-party IHDs and apps. The large majority of SMETS1 meters in Great Britain are due to be migrated by the end of 2026. If yours has not been migrated yet, ask your supplier for an update.

What SMETS2 unlocks that SMETS1 cannot reliably do

The features that really matter day-to-day are the modern smart tariffs.

• Time-of-use tariffs. Octopus Agile and similar half-hourly tariffs need half-hourly meter readings. SMETS2 sends those by default. SMETS1 cannot, unless migrated and even then with caveats.
• Smart EV charging tariffs. Octopus Intelligent Go, EDF GoElectric, OVO Charge Anytime and the rest all assume a working SMETS2 meter. If you are pricing an EV charger (see our best EV charger UK guide) and an Intelligent Go tariff together, a SMETS2 meter is part of the recipe.
• Solar export payments. Under the Smart Export Guarantee (SEG) your supplier pays you for surplus solar electricity. SMETS2 measures export every half hour, so you get paid for what you actually sent back, not an annual estimate. SMETS1 can be patchy — see our solar panel costs guide for how the export rate affects payback maths.
• Heat pump tariffs. Octopus Cosy and similar dedicated heat pump rates need SMETS2 for tariff pushes and time-of-use accuracy.
• Third-party in-home displays. The Hildebrand Glow IHD and the Bright app pair with SMETS2 meters via the DCC consent flow. They will not enrol an un-migrated SMETS1.

If you do not use any of those features today and never plan to, a working SMETS1 will not hold you back. If you are even considering them, SMETS2 should be the goal.

Can I upgrade my SMETS1 to a SMETS2?

There is no in-place software upgrade from SMETS1 to SMETS2 — the underlying hardware is different. What can happen instead is one of two things.

1. Your SMETS1 gets enrolled into the DCC network. This is the most common outcome and it happens remotely. You do not have to do anything. After migration, the meter behaves a lot more like a SMETS2: it survives supplier switches, accepts remote tariff updates, and supports more third-party IHDs.
2. Your SMETS1 meter is physically replaced with a SMETS2. This is done when the SMETS1 cannot be migrated, has a fault, or sits in a location with poor DCC signal. Suppliers do this for free if you have a documented fault or persistent dumb-mode issue. Under the Ofgem rules effective from 23 February 2026, your supplier has to respond to a smart meter fault within 5 working days and repair or replace within 90 days, or you get £40 automatic compensation per issue.

If your SMETS1 has been giving estimated readings since you last switched supplier, that is a documented fault. Call your supplier, ask for a SMETS2 replacement, and reference the 90-day repair window. Keep a log of the conversation including names, times and reference numbers. If they drag their feet beyond 90 days, the £40 compensation should be automatic, and you can escalate to the Energy Ombudsman.

How to verify a smart meter is actually accurate

This question comes up especially after a SMETS1-to-SMETS2 swap, when bills sometimes look different from what people expect. A few sanity checks.

1. Compare the meter's headline reading with the latest bill. Press the button on the meter and scroll to "Total kWh" for electricity or "Volume" for gas. The figure should match your latest bill's closing read, plus whatever you have used since.
2. Track daily usage with an independent monitor. A clamp-on energy monitor like the home energy monitor with CT clamp installs onto the main feed cable inside the consumer unit (electrician job, but quick) and reports usage to a phone app. Compare its daily totals with the smart meter's daily totals for a week. They should agree to within a few percent — if they do not, ask your supplier to run a meter accuracy test.
3. Check the in-home display matches the meter. If you have an IHD and the daily kWh on the IHD does not roughly match the daily delta on the meter itself, the IHD is the wrong one to trust — see our best smart meter in-home display guide for the displays that pair reliably.
4. Take a manual reading at the same time once a month and compare against the supplier's online portal. This is the simplest way to catch the rare case where the meter sends a corrupted reading.

Most smart meters are accurate to within ±1% — better than the analogue dial meters they replaced. The far more common issue is the IHD or the meter losing communication, which is a connectivity problem rather than an accuracy one.

What about SMETS3?

You may have seen mentions of "SMETS3" online. There is no SMETS3 specification in 2026 and none is currently published. The DCC has been consulting on what the next-generation smart meter standard should support — particularly around two-way EV charging (V2G), faster export settlement, and more granular load data — but any new specification would take years to ratify and roll out. If a salesperson tells you "you need SMETS3", they are making it up. SMETS2 is current.

Should you ask for a SMETS2 upgrade?

A simple decision tree.

• Your SMETS1 works fine, IHD shows real numbers, bills are accurate: do nothing. Wait for DCC migration. There is no benefit to demanding a SMETS2 swap.
• Your SMETS1 has been blank or dumb since a supplier switch: call your supplier, ask whether migration is scheduled in the next few weeks. If not, request a SMETS2 replacement under the Ofgem rules. It should be free.
• You want to move to Octopus Agile, Cosy, Intelligent Go, or any other half-hourly tariff and have a SMETS1: ask your supplier whether your meter has been migrated. If not, you will likely need a SMETS2 to qualify for the tariff.
• You are getting solar panels and want the best SEG export rate: insist on a working SMETS2. Half-hourly export readings are what unlock the higher SEG tariffs.
• You are getting a heat pump and want a heat-pump tariff: SMETS2 is effectively a prerequisite. Check this with your supplier before the heat pump install — see our heat pump running costs guide for why the tariff matters more than the kit.

You never have to pay for a SMETS2 replacement of a faulty SMETS1. If a supplier tries to charge you, push back and reference Ofgem's smart meter installation standards.

Frequently asked questions

Is SMETS2 better than SMETS1? In every practical sense, yes. SMETS2 survives supplier switches, supports half-hourly tariffs and SEG export, and works with third-party in-home displays. SMETS1 was the prototype and is being phased out via DCC migration and natural replacement.

Do I need to upgrade from SMETS1 to SMETS2? Only if your SMETS1 has problems or you want features it cannot deliver. A working, migrated SMETS1 is fine for a household that is not on a time-of-use tariff and does not have solar or an EV.

How long does a SMETS2 meter last? Smart meters are designed for a 15-year service life. Most will outlast that. The communications hub on top of the electricity meter typically gets replaced before the meter itself does.

Will my old IHD work with a new SMETS2 meter? Often yes, if the IHD is itself SMETS2-compliant (most Geo Trio II and Chameleon IHD3 units are). Your supplier will usually swap the IHD at the same time as the meter if there is a compatibility problem.

Are smart meters compulsory? No. Suppliers are required to offer them but you can refuse. Some smart tariffs (Octopus Agile, heat pump rates, EV tariffs) are only available to households with a working SMETS2, so refusing one closes those doors.

Is the SMETS1 enrolment programme finished? Not as of mid-2026. The DCC is still working through SMETS1 enrolment in rolling batches by manufacturer and region. The large majority will be done by the end of 2026.

The bottom line

For UK households today: SMETS2 is the standard, SMETS1 is the legacy, and the difference matters most when you switch supplier, want a smart tariff, or have solar. A working SMETS1 is not a problem; a dumb SMETS1 is a problem your supplier has to fix, free of charge, within 90 days. If you are not sure which one you have, call your supplier, then if you suspect issues, run through our smart meter problems guide. And if your smart meter is working but the supplier-issued IHD is not, our best smart meter in-home display comparison has the third-party options worth knowing about.

For the wider picture on what smart meters actually do for UK bills — including the £60-£250/year savings range and how to claim time-of-use tariffs — see the main Smart Meter Guide UK pillar.