The most important information about the heat cost allocator

But let's take a step back to the question of what a heat cost allocator actually does: heat cost allocators are mounted directly on the radiator – particularly wide radiators can even be equipped with two distributors – and usually have a metal back that conducts the heat of the radiator well. In this way, the heat units consumed can be optimally recorded.

Good to know: Heat cost allocators are recording devices and not measuring devices in the true sense of the word. They do not measure the amount of heat consumed in kilowatt hours or cubic meters, but record the heat consumption in a separate unit, the so-called heat unit. With the help of specific factors that depend on the type and size of the radiators, the actual heat consumption can be calculated from this unit. You can find out which individual factors are applied to each radiator in your heating bill.

By the way: In our guide we have the best Tips for saving on heating costs collected for you.

The terms heat cost allocator and heating meter are used synonymously. The heat meter, on the other hand, is a completely different device. In contrast to the heat cost allocator, which records the non-specific heat units, a heat meter – as it is technically called – measures consumption in physical units, typically in kilowatt hours (kWh) or megawatt hours (MWh).

A heat meter is installed in the supply lines of the heat supply and measures the temperature of the heating water both when entering the apartment and when it exits. Based on these temperatures, it calculates the amount of heat emitted to the apartment. Heat meters can therefore be used as an alternative to heat cost allocators for recording. They are particularly suitable for systems such as underfloor heating or for mixed use of real estate, for example as residential and commercial space. However, they are usually more expensive to purchase than heat cost allocators.

Alternatively, two heat meters can be installed behind a heating system in mixed-use properties, one of which is assigned to the commercial unit and the second records the heat quantity of the apartments. The amount of heat from the individual apartments is then divided among the individual users via heat cost allocators.

Basically, a distinction is made between two types of heat cost allocators: devices that use the evaporation principle for recording, and electronic devices, also known as digital or wireless heat cost allocators. The different types of devices have individual advantages and disadvantages:

• Evaporators: The detection device is equipped with an open glass tube, which in turn is filled with a special liquid. When the radiator gets warm, some of this liquid evaporates. At the end of the billing period, the liquid level in the tube determines the recording value. However, some of the liquid can evaporate even without the addition of heat. In order to correct potential measurement errors, the measurement service providers therefore regularly fill the tubes slightly beyond zero. Important: In low-temperature systems such as heat pump heating systems, the devices work too inaccurately because the flow temperature of the heating system is below 60 degrees Celsius and can therefore not be used. Heat meters are often used here instead. Important: The analogue evaporators may only be used until the end of 2026. More on this below.

A more modern form of analogue evaporation devices are the so-called capillary tube heat cost allocators. They have a very narrow tube that contains only a small amount of measuring liquid. The special design and the longer scale serve to minimize measurement and reading errors. Often, the devices even have two parallel measuring tubes: one is used for billing the current heating season, while the other is sealed and displays the comparative value from the previous year.

• Electronic heat cost allocators: Modern heat cost allocators work purely electronically and have at least one temperature sensor, a computing core and a display. Models with two sensors continuously record the temperature difference between the radiator and the room air. Devices with only one sensor, on the other hand, set a fixed base value for the room temperature and therefore work somewhat less accurately. In principle, however, electronic heat cost allocators are characterized by higher accuracy and can also correct measurement errors caused by external heat sources such as solar radiation. They store the recorded values on a monthly or annual basis and enable remote reading. In addition, reading errors, faults or manipulation attempts can be identified by a special checksum.

With the amendment to the Heating Costs Ordinance in 2021, the new installation of remotely readable meters for the consumption-based recording of heating and hot water costs became mandatory. However, there is a transitional period until 2026 for the existing measurement technology, and the use of remotely readable meters and thus wireless heat cost allocators will not become mandatory until 2027. For the reading, it is then no longer necessary for third parties to enter the apartment.

Good to know: Heat cost allocators are mandatory to use in apartment buildings. However, there is an exception for buildings with only two apartments, one of which is occupied by the landlord himself. In this case, the landlord and tenant can stipulate in the rental agreement that the Heating Costs Ordinance does not apply and that the heating costs are billed at a flat rate, regardless of actual consumption. This regulation also applies to granny flats, provided that one of the flats is occupied by the landlord. If there are commercial units in the building in addition to the apartments, or if two condominiums in a building belong to different owners and are rented, the Heating Costs Ordinance applies.

More about the Amended Heating Costs Ordinance can be found out in our large information guide.

Ein elektronischer Heizkostenverteiler verfügt über keine Tasten zur Aktivierung, daher wechselt das Display automatisch zwischen verschiedenen Werten. Bei sogenannten fortlaufenden Geräten lässt sich lediglich der aktuelle Verbrauchswert ablesen. Auch der Anzeigentest und die Prüfzahl werden angezeigt. Bei stichtagsprogrammierten Heizkostenverteilern wird auch der Verbrauchswert des vergangenen Jahres angezeigt. Um die einzelnen Variablen klar zu identifizieren, ist üblicherweise jedem Wert ein spezifischer Buchstabe zugeordnet:

A: Current consumption value or consumption since the last reference date

M or C: Display test to check the functionality of the display

K: Next deadline on which the billing period ends, the device stores the consumption value and then resets it for the start of the new billing period

M: Total consumption of the previous billing period; if no cut-off date is set, four lines can be seen next to the "M" (for "Memory")

V: Consumption of the last heating season (always from 1 January to 31 December)

L: Six-digit device number

Electronic heat cost allocators can basically be read by yourself, which can be useful for tenants to check their heating bill and compare it with the previous year's consumption. However, the transmission of the measured values is automatic by radio for most digital models, and from 2027 this will even be mandatory. So you don't necessarily have to read the distributor yourself. In the case of heat cost allocators based on evaporation, even readings are not legally valid, which is why it makes little sense to read these devices independently.

Important: No direct conclusions can be drawn about the actual heating costs from the values you read yourself, as heat cost allocators do not record consumption in physical measured variables. Only by applying an individual distribution key can the actual heating costs be determined. This is done in the utility bill.

Landlords have the option of passing on the costs of reading the heat cost allocators to the tenants. According to the Heating Costs Ordinance, at least 50 percent of the total costs must be determined via heat cost allocators or heat meters. Between 30 and 50 percent of the costs may be billed as consumption-independent basic costs, based on the living space.

source : Heat cost allocator: The most important information in the big FAQs (enercity.de)