Does an intermediate meter need to be certified to bill against it?

Billing sub-meters fall under the Measuring Instruments Directive

In most cases, a meter that determines what someone must pay must comply with European requirements for measuring instruments. These requirements are set out in the Measuring Instruments Directive (2014/32/EU) and apply specifically to electricity meters that convert consumption into a billing amount. A meter that only provides an informational indication of consumption, without a bill directly attached to it, generally falls outside these requirements. However, once a meter forms the basis for what a guest must pay — such as when billing electricity consumption in a holiday rental — there is a good chance that the meter must comply with the statutory requirements for measuring instruments.

For those billing electricity to guests, this means in practice that the chosen sub-meter must have the correct certification and markings, as described in the directive for electricity meters. This is not a matter of "may or may not", but a factor that plays a role in selecting hardware: a meter without this certification is not automatically suitable for converting consumption into money, even when payment takes place via an app or separate system rather than through a regular energy supplier.

What the directive and RDI say about this

This conclusion follows from Annex V of the Measuring Instruments Directive (2014/32/EU), which sets specific requirements for electricity meters used to determine a billing amount. The Rijksinspectie Digitale Infrastructuur (RDI) is the Netherlands' supervisory authority for electricity, gas and heat meters and describes on its website which meters must comply with these requirements and why this is relevant for billing applications. For the precise requirements and the current state of affairs, the RDI refers to its own information pages on this subject.