DUSAN PETKOVIC - stock.adobe.comUnderfloor heating systems are enjoying increasing popularity – they provide even warmth and significantly increase living comfort. They are usually a standard feature in new buildings. However, the desire to install underfloor heating in addition to existing radiators is also growing in existing buildings.
Technically, this is feasible. However, landlords then face an important question: How can a mixed heating system consisting of underfloor heating and radiators be billed in a legally compliant and transparent manner for all tenants?
Types of underfloor heating and their impact on billing
Electrically operated underfloor heating
- Thin heating mats or films under the floor covering
- Electric operation, no connection to the central heating system
- Billing is done separately based on electricity consumption.
- No impact on the central heating cost bill
- A combination with radiators is unproblematic.
Water-based underfloor heating systems
- Hot water operation with connection to the existing heating system
- A common solution for retrofitting existing buildings
- The temperature must be lowered via an RTL box in the return line.
- Must be integrated into the central heating cost statement.
- Requires special measuring equipment
Who in this case Combined billing of underfloor heating and radiators Anyone wishing to do so must carefully examine the metrological requirements.
How can combined heat consumption be recorded in a legally compliant manner?
Option 1: Heat meter per residential unit
- Joint recording of total heat consumption (radiators + underfloor heating)
- No need to differentiate between individual heating surfaces
- Full compliance with the heating cost regulations
- Recommended solution for retrofitting
This option is ideal if you Combined billing of underfloor heating and radiators want.
Option 2: Heat cost allocators on radiators
- Only radiators are detected.
- Underfloor heating is not taken into account.
- Combination with a heat meter is not permitted (§ 5 para. 7 HKVO)
- According to the German Federal Court of Justice (BGH) ruling (VIII ZR 57/07), calculations of differences are inadmissible.
- Legally compliant billing not possible
What is permitted in mixed heating systems?
A combined system is only legally permissible if consumption is recorded uniformly – for example, with one heat meter per apartment. A mix of heat cost allocators and heat meters is not permitted according to the Heating Costs Ordinance.
What landlords should consider before retrofitting
- Check existing measurement technology
- Consider switching to heat meters for heat cost allocators.
- Always plan retrofits with billing in mind.
- Get Minol's expertise early on – we support you with all questions relating to planning, technology and billing.
Recommendation for practical application
If you Combined billing of underfloor heating and radiators If you want to ensure legally compliant, transparent, and fair heating cost billing, rely on complete consumption recording using heat meters.
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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