What Are MID Standards in Metering? MI-001, MI-002, MI-003, MI-004 Explained

MID Standards for Metering Explained: What MI-001, MI-002, MI-003, and MI-004 Mean

If you're working with metering devices, whether for water, gas, electricity, or heat, understanding the MID standards for metering is essential. The MID, or Measuring Instruments Directive (2014/32/EU), defines the legal and technical requirements for meters used for billing across the EU and UK.

In this guide we’ll explain the MID standards, break down the different MI codes (MI-001 to MI-004), and help you determine which apply to your metering application.

What is MID (Measuring Instruments Directive)?

The MID (Measuring Instruments Directive) is an EU regulation that metering and measuring devices used for commercial purposes are:

• Accurate

• Reliable

• Legally compliant

Any meter approved under MID is CE-marked and includes an MID marking (e.g., M21 for meters certified in 2021). MID-compliant meters are required for all billing and sub-metering applications across much of Europe and the UK.

Why Do MID Standards Matter?

If you use meters for charging tenants or customers for utilities, the law often requires those meters to be MID-approved. Using non-compliant meters can:

• Invalidate billing

• Breach regulations

• Undermine trust with tenants or clients

MID Modules Explained: MI-001 to MI-004

Each MID module (MI-XXX) refers to a specific category of measuring instrument. Here's what each one covers:

MI-001 — Water Meters

What it covers:
Meters that measure the volume of cold or hot water supplied through a pipe.

Applications:

• Domestic water metering

• Commercial and industrial water billing

• Multi-dwelling properties

Example MID-compliant products:

• Apator PoWogaz single-jet and multi-jet meters

• Apator PoWogaz woltman meters

• Apator PoWogaz ultrasonic meter

• ---

MI-002 — Gas Meters and Volume Conversion Devices

What it covers:
Devices used to measure gas volume and convert it to standard conditions (temperature and pressure).

Applications:

• Domestic gas supply

• Industrial and commercial gas metering

• Combined gas meter and volume converter systems

Example MID-compliant products:

• Honeywell BK-G Diaphragm Meters

• Honeywell RABO Rotary Meters

• Honeywell EK205, EK220 and EK280 Volume Converters

MI-003 — Active Electrical Energy Meters

What it covers:
Electricity meters that measure active energy (kWh) consumed over time.

Applications:

• Utility company electricity meters

• Smart meter installations

• Commercial energy sub-metering

Example MID-compliant products:

• Apator Norax 1 & 3 Electricity Meter

• Eastron SDM range of DIN rail Electricity Meters

• Emlite ECA2 & EMP1 Electricity Meters

MI-004 — Heat Meters

What it covers:
Thermal energy meters that calculate energy transferred in a heating or cooling system.

A heat meter typically includes:

• A flow sensor

• Two temperature sensors

• A calculator unit

All components must be assessed as a system to be MID MI-004 approved.

Applications:

• District heating schemes

• Apartment blocks and communal heating

• Energy billing for heat or cooling

Example MID-compliant products:

• Sontex SuperStatic meters

• Danfoss ultrasonic meters

• Siemens ultrasonic meters

Other MID Categories (MI-005 to MI-010)

How to Check If a Meter Is MID-Compliant

Look for these indicators:

• CE Marking

• MID Year Mark (e.g., M24)

• Declaration of Conformity

• Product datasheet listing MID module (e.g., “Conforms to MI-004”)

FAQs: MID Standards for Metering

❓ Is MID certification required in the UK?

Yes. The UK continues to recognise MID standards post-Brexit for billing purposes.

❓ Can I use a non-MID meter for monitoring only?

Yes. MID is only required for financial transactions such as tenant billing.

❓ Are all parts of a heat meter tested under MI-004?

Yes, the flow sensor, temperature sensors, and calculator must all be approved as one unit.

Summary: Choosing the Right MID Module

Understanding the difference between MI-001, MI-002, MI-003, and MI-004 helps ensure you’re selecting the right metering solution — whether you're metering water, gas, electricity, or heat.

For metering that is legally compliant and suitable for billing, always ensure your devices are MID-certified under the appropriate module.

Need Help Choosing the Right MID Meter?

At DMS Metering Solutions, we provide a full range of MID-approved water, heat, and utility meters from leading brands including Sontex, Apator PoWogaz, Elvaco, and Honeywell.

👉 Contact us for expert guidance and product recommendations.

01773 534555  / meters@dmsltd.com