Electric, Gas & Water Sub Meters: Differences, Use Cases & Standards

Energy management isn’t just about electricity. Businesses across the UK also need visibility of gas and water consumption to manage costs, meet compliance, and drive Net Zero progress. Sub-metering provides the answer, but not all sub-meters are the same.

This guide breaks down the differences between electric, gas, and water sub-meters, explaining where each is used and the standards you need to know.

Electric Sub Meters

• Applications: Lighting, HVAC systems, EV chargers, production lines.

• Types:

  • Single-phase sub-meters for light loads.

  • Three-phase sub-meters for heavy industrial machinery.

  • Digital sub-meters with real-time monitoring and cloud connectivity.

• Standards: Must be MID-approved for billing. Where integrated with on-site generation (CHP, solar, battery storage), G99 compliance is essential.

Gas Sub Meters

• Applications: Boilers, combined heat and power (CHP) systems, process heating.

• Types:

  • Diaphragm meters for lower flows.

  • Turbine meters for higher flows.

  • Ultrasonic meters for precision and low maintenance.

• Benefits: Track gas consumption for cost allocation, carbon reporting, and efficiency optimisation.

• Compliance: Use OFGEM-approved meters for billing accuracy.

Water Sub Meters

• Applications: Cooling towers, food & beverage processes, tenant billing.

• Types:

  • Mechanical meters (basic, lower cost).

  • Ultrasonic meters (accurate, reliable, no moving parts).

  • Smart water meters (real-time leak detection and cloud reporting).

• Benefits: Identify leaks, reduce waste, allocate costs fairly across tenants or processes.

How to Choose the Right Sub-Meter

1. Define purpose → Billing, monitoring, or compliance?

2. Choose accuracy → For billing, use MID-approved. For monitoring, mid-range digital options may suffice.

3. Select data granularity → Do you need 5-minute real-time data or monthly reads?

4. Integration → Will your sub-meters connect with BEMS or dashboards?

Why Multi-Utility Sub-Metering Matters

Electricity is just one part of the energy picture. Businesses with large heating or water use must include gas and water sub-metering to capture true Scope 1 & 2 emissions.

Multi-utility sub-metering:

• Improves reporting accuracy.

• Reduces hidden costs like water leaks or inefficient boilers.

• Supports Net Zero and ESG commitments.

FAQs

Q: Can I see electric, gas and water sub-meters on one dashboard?
A: Yes, cloud platforms integrate multiple utilities into a single reporting system.

Q: Do sub-meters replace supplier meters?
A: No. They provide additional internal detail, supplementing your supplier’s meter.

Q: Are water and gas sub-meters as accurate as electricity sub-meters?
A: Yes, when correctly specified and calibrated to UK standards.

Next Steps

Sub-metering across electricity, gas and water provides the complete picture businesses need to save costs and meet reporting obligations.