Knowledge: Heat meters
Heat metering –
a guide for installers
Heat meters are an essential element in many renewable installations to claim
payments under the RHI, but much confusion persists over their usage. Mark
Krull, director for Logic Certification, explains the types of applications where heat
meters are required
or the most part, homeowners receive RHI tariff payments
based on estimated heat use or generation. In instances
where it is not possible to estimate this, the scheme
requires a heat meter, which regularly submits readings to
work out how much the customer is owed.
Heat meters measure the heat output from the renewable
technology and any back-up heat system. In the case of heat pumps
and electric back-up heaters, electricity consumed is also measured.
F
Heat meter applications:
•
If the heating system is bivalent, combining a heat pump, for
example, with a fossil fuel system, like a gas boiler, within the
same product.
•
If a biomass boiler or stove has an installation capacity which
does not provide 100 per cent of the space heating requirement.
•
If the property was occupied for less than 183 days of the previous
year.
•
If there is a back-up space heating system in the property, i.e. an
eligible renewable heating system installed alongside another
fossil-fuel space heating system. You don’t need metering,
however, if your back-up heating is an electric heater controlled
by the same system as the renewable system.
•
•
Where the metered output includes heat from an additional
ineligible technology. This might be where a heat meter has
been installed after a standalone DHW cylinder that uses some
form of supplementary input (electric immersion heater or a twin
coil cylinder with the secondary coil fed from a gas or oil boiler);
or where an ineligible heat source is simply contributing to the
metered heat output.
A heat pump used in cooling mode during the summer months.
This will reduce scheme payments due to the additional metered
electrical consumption.
Heat meter installer checklist
•
Label all heat meters so the customer understands what each bit
of kit does.
•
Provide the customer with a signed and completed paper copy
of the ‘Installer Metering Questions’ (IMQs), including the first
meter reading so they can receive RHI payments. End users need
this information to complete the metering questions in their RHI
application – ideally, you should help them fill this in.
•
Show your customer how to read the heat meter so they can take
future readings.
•
Provide photos of the meters, showing their labelling, Measuring
Instruments Directive (MID) compliance and initial readings.
If two of the same renewable heating systems are commissioned at the
same time (e.g. two air source heat pumps) that is considered to be one
heating system, so will not require metering.
Metering and Monitoring Service Package (MMSP)
The MMSP is an optional extra, similar to a service contract. Designed
for owners of biomass pellet boilers or heat pumps, heat meters
and temperature sensors are connected to a software package that
monitors and records the system performance. The MMSP provides
information for DECC, in order for the effectiveness of the scheme to be
evaluated, so recipients receive additional funding to cover the MMSP
set-up.
Alternative metering requirements
There are certain instances where the installation requires an
alternative heat metering arrangement. These scenarios include:
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