KNX Energy Metering

KNX energy meters are installed in the distribution board and measure current, voltage, active power (W) and cumulative consumption (kWh). Measured values are transmitted as KNX telegrams via communication objects (COs) and can be received by any device on the bus.

Active power uses DPT 9.024 (2-byte float, unit W), energy quantities use DPT 13.010 (4-byte signed integer, unit Wh) or DPT 14.056 (4-byte float, kWh). The exact DPT depends on the device manufacturer, the ETS product catalogue specifies the DPT for each CO.

Measurement intervals are device-specific: many meters send on change (when delta exceeds n%) and additionally in cycles (e.g. every 60 seconds). Shorter cycles load the bus unnecessarily; 30–60 seconds is common in practice.

Typical use cases are individual circuit metering (heat pump, EV charger, air conditioning) and total building consumption for feed-in and grid-draw metering. For photovoltaic systems, a second meter channel can be used to calculate self-consumption ratios.

KNX visualisation systems (e.g. IP visualisation, graphical panels) can display and historise energy values live via group addresses. Alternatively, many building automation servers (Home Assistant, KNX IP interfaces) write values directly to databases for long-term analysis.

venfree shows energy metering as a function in the planner. When you plan an energy meter for a load, the solver automatically recommends suitable KNX measuring devices (e.g. MDT AMS series) as a supplement to switching or dimming actuators.