Smart meter: definition and meaning

A smart meter is a gas or electricity meter that measures your energy use in short intervals, usually every half hour, and sends the readings to your supplier over a secure wireless network. Nobody needs to come and read it, and it usually comes with an in-home display showing what you are using and what it costs.

SMETS1 and SMETS2

Smart meters in Great Britain are built to government technical specifications, the Smart Metering Equipment Technical Specifications (SMETS).

Generation	What it means
SMETS1	The first meters, installed by individual suppliers on their own systems. Many lost their smart functions when a customer switched supplier until they were moved onto the national network.
SMETS2	The current standard. They connect to the national smart metering network from the start, so they keep working when you switch.

A meter that has stopped sending readings is said to be running in “traditional mode” and has to be read by hand.

How many are installed

According to the Department for Energy Security and Net Zero (DESNZ), at the end of June 2026 there were about 42 million smart and advanced meters in homes and small businesses across Great Britain, 72% of all meters. Of roughly 40 million smart meters, 92% were operating in smart mode. Suppliers installed about 1.1 million smart and advanced meters between April and June 2026, counting both first-time installations and replacements.

What a smart meter makes possible

Accurate bills based on actual readings rather than estimates.
Time-of-use tariffs, which charge different prices at different times of day and need half-hourly readings.
Export payments for solar panels under the Smart Export Guarantee, which require a meter that records exported electricity.
Flexibility schemes that reward households for shifting use away from peak times.

Having a smart meter does not by itself lower your bill. Any saving comes from what you change in response to the information or the tariff you choose.