From 1 January 2023, requirements apply to heat meters not only at the point of sale, but also during use. The Norwegian Metrology Service will therefore supervise that the user has a system in place to ensure compliance.
The user of a heat meter is the party that supplies heat to customers in a heat exchange circuit for payment, and who owns the heat meter. In practice, the user of a specific heat meter will in most cases be the district heating company responsible for invoicing based on that meter.
The new requirements for heat meters are based on the principle that the user must have an internal control system for their meters. This internal control must ensure, among other things, that the meters are suitable, correctly installed, and within the regulation’s requirements for maximum permissible measurement error. Central to internal control is a metrological self-check of heat meters used for financial settlement.
Where conditions permit, the Norwegian Metrology Service recommends that this self-check be carried out as a sample-based inspection. This method involves dividing all the user’s meters into groups with meters of the same type, installation period, and similar operating conditions. A random selection of a certain number of meters from each group is then inspected. The results of each sample inspection are considered representative for the entire group.
The Norwegian Metrology Service recommends that a group of meters undergo a sample inspection no later than 8 years after the first meter in the group was installed. The number of meters to be inspected depends on the total number in the group and the meter size. Sample-based inspection is resource-efficient, as only a proportion of meters are checked after 8 years, and the result of this inspection is assumed to apply to all meters in the group.
When water or heat meters are inspected, this must be done using reference equipment and methods that ensure sufficient traceability to the International System of Units (SI).
For heat meters, the Norwegian Metrology Service considers it most appropriate to send the entire meter to a calibration laboratory. The user may freely choose a competent calibration laboratory in or outside Norway.
It is the user’s responsibility to ensure that if external companies are used for meter inspections, these have sufficient competence. Proof of competence may, for example, be accreditation for calibration of water or heat meters. The Norwegian Metrology Service has no approval scheme for companies, but may, if necessary, request to carry out a voluntary audit of companies that perform tasks related to water and heat meters. The Service may also, if necessary, issue individual decisions requiring such external service providers to implement their own internal control for measuring instruments and measurements.
The terms consumer, customer and subscriber are often used for those receiving district heating from a supplier. The Norwegian Metrology Service has chosen mainly to use customer or district heating customer as the term for recipients of district heating.
District heating – or heat energy, as it is referred to in the regulation – is generally measured using a so-called heat meter. This meter consists of a flow meter that measures how much liquid has passed through, and a pair of temperature sensors that measure the heat emitted. The district heating supplier is responsible for ensuring that the heat meter is authorised for use. This includes ensuring that measurement error does not exceed the permissible limits and that the meter is approved in accordance with applicable rules.
The district heating supplier is responsible for ensuring that the heat meter measures correctly, and must therefore be contacted if you suspect a fault. The applicable procedures in such cases are usually described in the supplier’s terms and conditions. The Norwegian Metrology Service cannot intervene in conflicts between a customer and a supplier, but has a duty to provide guidance on relevant regulations and other pertinent matters.
If you live in a housing cooperative, several apartments may receive district heating through the same meter. In such cases, the cooperative is usually considered the customer in relation to the supplier. To distribute common costs according to actual consumption, many cooperatives install individual meters for each apartment in addition to a common meter. In such cases there is no direct customer relationship between the district heating supplier and each apartment, and responsibility for the heat meter often falls on the party considered the economic counterparty for payment of heat consumption.
The Norwegian Metrology Service offers on-request verification as one of our services. As a neutral third party, we can carry out verification and in-use inspections and issue documentation. We have the equipment and expertise to help your enterprise meet the requirements for measurements.
We supervise that the supplier’s internal control system for heat meters meets the metrological requirements of the regulation.
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64 84 84 84
E-mail:
postmottak@justervesenet.no
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