Philipp Reinhard - © Philipp Reinhard, 2016
Why do consumption readings appear even when valves are closed, and what impact does this have on heating costs? Electronic heat cost allocators register consumption even though the thermostatic valves are closed. This is due to minimal heat loss from the heating water, which is not differentiated by the system. This phenomenon occurs particularly frequently with small radiators and single-pipe heating systems. The readings are usually small and cause hardly any financial disadvantage.
Why does the electronic heat cost allocator show consumption when the heating is switched off?
Electronic heat cost allocators They also register minor heat losses, but cannot distinguish between intended and unintentional consumption. This means that heat cost allocators can sometimes register heat loss even when the thermostatic valves are closed. This is initially confusing for landlords and tenants, as nobody wants to pay for unused heat.
This phenomenon occurs primarily in vacant or unheated apartments, often with modern, sensitive electronic heat cost allocators. The following are particularly affected:
- Vertical and horizontal single-pipe heating systems
- Small radiators in kitchens and bathrooms
- Systems with relatively high flow temperatures
DOG-Pix – stock.adobe.comHow does the consumption occur despite the valve being closed?
Even when the thermostatic valve is closed, hot water continues to flow through the radiator return pipe. The heat is generated by:
- Heat conduction via the metal fittings
- Convection flow in the return connection
- Heating of the radiator in the area of the inlet and outlet
Even with small radiators and low heat output, this heat can be sufficient to be detected by the electronic heat cost allocator. The heat cost allocator measures from a temperature difference of 4 Kelvin to the room or from a radiator temperature of 30 degrees Celsius. The technical requirements of DIN EN 834 must be observed.
Technical solutions and their limitations
Theoretically, backflow preventers could reduce the effect by blocking the return flow of heating water. In practice, however, these measures are often more expensive than the potential savings from lower consumption readings. Electronic heat cost allocators count every measurable heat output, even if it is minimal and not caused by the user.
Conclusion: Electronic heat cost allocators usually show consumption without problems even when the heating is switched off.
Displaying consumption figures when radiators are turned off is technically explainable and not a measurement error. The consumption values are usually very low and result in minimal costs. It is important for landlords and tenants to know that billing is based on actual heat output and that the meters are functioning reliably.
contrastwerkstatt – stock.adobe.comHeating bill from a professional
Brunata Minol supports you with digital measurement technology and radio transmission and in providing interim consumption information via app – secure, digital and compliant with the German Heating Cost Ordinance (HKVO).
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