Energy Metering and Sub-Metering
A clear explanation of how electrical energy is measured, the difference between the utility meter and sub-meters, what quantities a smart meter records, and why sub-metering is central to managing energy in buildings.
An energy meter measures how much electrical energy passes a point in a circuit, recorded in kilowatt-hours (kWh). The utility’s revenue meter at the building’s incoming supply is the basis for the bill. Sub-meters placed deeper in the installation measure energy used by individual tenants, floors, or systems, so consumption can be allocated and managed rather than guessed.
Sub-metering turns a single building bill into actionable information. It answers who used what, which systems dominate consumption, and whether efficiency measures are actually working. In a region where cooling and pumping use large amounts of electricity, this visibility is the foundation of any serious energy-management or net-zero effort.
How it works
What a meter measures. A basic meter measures real energy in kWh — the product of power and time. Modern smart meters measure much more: voltage, current, real power (kW), apparent power (kVA), power factor, reactive energy (kVArh), maximum demand and often harmonic distortion, giving a full picture of how a circuit behaves, not just how much it consumes.
How it senses current. For small loads a direct-connected meter passes the full circuit current through itself. For larger loads a current transformer (CT) clamps around the conductor and feeds a small proportional current to the meter, which scales it up — allowing one meter to measure very large feeders safely.
Utility, check and sub-meters. The utility revenue meter is owned by the distribution authority and sets the bill; it is sealed and certified for accuracy. A check meter lets the owner verify the utility reading. Sub-meters, owned by the building, measure energy below the main intake — per tenant, per floor, or per system such as HVAC, lighting and small power.
Communication and data. Smart meters communicate over protocols such as Modbus or via pulse outputs to a building management system or dedicated energy-monitoring platform. The data is logged, trended and turned into dashboards and reports, allowing tariffs, benchmarks and alarms for abnormal use.
Accuracy and billing integrity. Meters carry accuracy classes, and CTs must be correctly rated and wired for the reading to be trustworthy. Where sub-meter data is used to bill tenants, the metering must be accurate, tamper-evident and traceable, so disputes can be resolved against reliable records.
Main types
In the UAE
- In the UAE, the revenue meter at the building intake is provided and sealed by the distribution authority (such as ADDC or DEWA), and the connection and metering must meet that authority’s requirements.
- Sub-metering supports Estidama Pearl and energy-efficiency goals by making cooling, pumping and lighting consumption visible so it can be benchmarked and reduced.
- For solar and net-metering schemes, approved bi-directional metering records both imported and exported energy in line with the distribution authority’s rules.
How GPR applies this
GPR designs and installs energy metering and sub-metering for residential, commercial and industrial buildings across Abu Dhabi, selecting direct or CT-operated smart meters and locating them to capture tenant and system consumption accurately. We coordinate the utility revenue meter with ADDC/DEWA requirements, wire and configure CTs correctly, and integrate meter data into the building management system so owners get clear dashboards, tenant billing and verified efficiency reporting.
Frequently asked questions
What does an energy meter actually measure?
At minimum it measures real energy in kilowatt-hours; smart meters also record voltage, current, power, power factor, demand and often harmonic distortion.
What is the difference between a utility meter and a sub-meter?
The utility revenue meter at the building intake sets the bill and is owned by the distribution authority; sub-meters are owned by the building and measure energy used by individual tenants, floors or systems.
When is a current transformer (CT) meter needed?
For larger feeders where it is impractical or unsafe to pass the full current through the meter; the CT feeds a small proportional current that the meter scales up.
Why is sub-metering useful?
It turns a single bill into actionable data — showing who used what and which systems dominate consumption — so cost can be allocated fairly and efficiency measures verified.
Can sub-meters be used to bill tenants?
Yes, provided the metering is accurate, tamper-evident and traceable so consumption can be allocated reliably and disputes resolved against trustworthy records.