Heat meter

A heat meter measures how much heat your heat pump delivers. Together with the electricity meter, this allows you to determine the actual seasonal performance factor (SPF).

A heat meter measures the amount of heat that your heat pump delivers to the heating system and hot water, usually in kilowatt-hours. To do this, it records the water volume and the temperatures in the flow and return.

Why you need it

Without measurement, you do not know how efficiently your system is actually running. klimaaktiv explicitly advises having meters installed: only data on generated heat and electricity consumption makes efficiency visible. The klimaaktiv Wegweiser (guide) requires a heat meter and a separate electricity meter for the compressor and all auxiliary drives of the heat pump, unless these are already integrated into the device. According to the Wegweiser (guide), the heat meter does not need to be calibrated.

How to calculate the seasonal performance factor

Read both meters once a year on the same day. Divide the generated heat by the electricity consumed. The result is the seasonal performance factor of your system. Example: 12.000 kWh of heat divided by 3.000 kWh of electricity gives an SPF of 4.

What you should look out for

• Many heat pumps measure the heat quantity internally. Ask how accurate these values are and whether the heating element is included in the count.
• According to the Wegweiser (guide), instructions for determining the SPF should be enclosed with the system.
• If the measured SPF deviates significantly from the planning, it is worth talking to the installer.

You can read more about what you should check after commissioning under after installation.

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