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SMETS 2 Meters

Types of Smart Meter

There are two main types of smart meters - the older models known as SMETS 1 (Smart Meter Equipment Technical Specifications) and the newer versions that were first rolled out in 2018, known as SMETS 2.

SMETS 2

This specification is more advanced. A more modern communication network is used with these meters called the Wide Area Network, and all suppliers will use this - keeping your smart meter smart when switching suppliers.

To understand the progress and factors affecting the roll-out of these meters see Meter Roll-Out.

Number of SMETS 2 Meters

By 31^st March 2026 26,328,660 SMETS 2 meters had been successfully installed and set up in DCC's systems.

Additionally, by the same date, some 11,445,417 SMETS 1 meters were operating through the DCC's systems following migration from their original control systems.

SMETS 2 Meter Models

Nearly all meters being currently installed are SMETS 2. If you are wondering if you have a SMETS 2 meter, look up your meter model number in the table below which lists all currently approved SMETS 2 meters.

ESME = Electricity Smart Metering Equipment
GSME = Gas Smart Metering Equipment.

2A Aux means the meter has a auxiliary control circuit rated at a maximum of 2A. The rating is too low to control heating loads directly so this auxiliary control must be fed into a Contactor.

Diaphragm type gas meters have been used for many years. Within the meter there are two or more chambers formed by movable diaphragms. With the gas flow directed by internal valves, the chambers alternately fill and expel gas, producing a nearly continuous flow through the meter. As the diaphragms expand and contract, levers connected to cranks can link to a counter or provide an electrical pulse to measure the gas volume.

Five terminal (5T) electricity meters have an additional live connector for an off-peak load switched by an internal timer. The other four terminals are live and neutral in, and 24 hour live and neutral out.

Four terminal (4T) electricity meters are the most commonly used meters. The four terminals are live and neutral in, and live and neutral out.

Semi-concealed gas meters are installed against the outer wall of a building and partially buried into the ground.

Seven terminal (7T) will be twin element or dual rate electricity meters with an additional live connector for an off-peak load switched by an internal timer.

Thermal Mass meters measure the amount of gas used by monitoring the cooling effect of gas on sensors.

Twin Element or Dual Rate meters can measure the load in different circuits independently, meaning load can be measured for two different price rates at the same time. Usually, one circuit will be for normal domestic load and the other for heating.

Ultrasonic gas meters measure very small difference in time that it takes an ultrasonic pulse to travel with and against the flowing gas stream. A microprocessor can then calculate the gas used. The main advantages of ultrasonic gas meters are that they have no moving parts and are therefore more reliable, and they are more accurate than Diaphragm gas meters.

SMETS - Gas Meter Battery

SMETS 1 and 2 gas meters are powered by a battery, as it would be dangerous to power them from the mains electricity supply.

The lithium battery is expected to last between 10 and 20 years, although this can vary greatly depending on the battery demand. To keep demand low the gas meter only talks to the communications hub every 30 minutes, although the demand on the battery increases greatly if firmware updates are downloaded.

When the battery is low some meters may show an indication on the screen, and some may omit a short beep. They also send an alert to the supplier to let them know the battery is getting low, but unfortunately suppliers do not usually act on this due to lack of monitoring systems and poor maintenance policies - their focus is on new installations.

If you see that your gas meter battery is dead let your supplier know.

When the battery is dead the gas meter will stop recording and the supplier will make estimates for billing.

The gas meter battery cannot be replaced by the customer but must be replaced by the supplier or their agents. In practice suppliers usually swap the gas meter for a new one rather than replacing the battery.