Reader question: Does the flat 15 percent maintenance deduction really apply to my heating replacement?
The new heating system has been installed. The rent increase calculation shows a flat deduction of 15 percent for maintenance. That can fit the special calculation route. In the version in force on the date of research, however, the provision contains an explicit exception. An older calculation graphic with only a single flat calculation scheme is therefore not sufficient for your case.
First establish which increase route was chosen
§ 559e BGB requires certain heating modernisations, the subsidy prerequisites to be met in principle and actually claimed third-party funds. It generally provides for an annual increase of ten percent of the costs incurred for the flat, less any third-party funds claimed. For missing subsidies it refers under its conditions to § 559. [BGB559e]
The mere invoice from a heating company therefore confirms neither the special route nor the complete cost basis. Ask about the type of measure, completion, treatment of subsidies and the expressly applied provision. The general route under § 559 has a different system. [BGB559]
The exception is part of the current rule
Paragraph 2 of § 559e generally provides for a flat share of 15 percent for necessary maintenance measures that is not part of the costs incurred. Immediately afterwards it excludes costs from the installation of a heating system within the meaning of § 43 GModG from that. [BGB559e]
§ 43 concerns certain systems supplied with gas, heating oil or liquefied gas, newly installed after its installation cut-off date, and other situations regulated there. [GMODG43] Whether your particular system falls under it must be examined on the basis of the actual measure. The article does not perform a complete technical compliance check and does not extend the exception to any arbitrary heating system.
Two fictitious system files
For Flat A the document names a system whose assignment to the special route and to the flat rate initially appears plausible. The advice examines subsidy data and actual costs. For Flat B the documentation, by contrast, points to a system under § 43 GModG. There the exception is specifically investigated, rather than automatically adopting the same 15 percent line.
The cases deliberately contain no finished euro results. The same calculation with different system designations would skip the decisive legal junction. For older measures the relevant temporal legal status and transitions must also be assessed separately.
The flat rate is only one calculation step
Even a correctly treated maintenance share does not yet confirm the entire increase. § 559e contains its own limitation of the monthly increase to €0,50 per square metre within six years and refers to further rules. [BGB559e] Already considered increases, correct apartment allocation and individual objections must therefore also be checked.
File the notice and the later increase declaration separately. § 559b requires an explained calculation; the commencement of payment is a separate question. [BGB559b] This article does not calculate an individual due date and does not replace advice on hardship cases.
Ask the specific follow-up question
Request a comprehensible statement as to why the flat deduction was applied or on what current exception it was not applied. Attach the system description and data. That turns “The invoice is wrong” into a point that can be reviewed. The technical decision arises from the applicable provision and the actual system, not from a memorised percentage figure.