Heizungstausch in a WEG: what the new heating law (GModG) means in Nuremberg

What changed in summer 2026

Under the previous Building Energy Act (GEG), the 65 per cent rule would have applied in large cities such as Nuremberg from 1 July 2026: newly installed heating systems would have had to run on at least 65 per cent renewable energy. That never happened. The deadline was first postponed, and on 10 July 2026 the Bundestag and Bundesrat passed the Building Modernisation Act (Gebäudemodernisierungsgesetz, GModG). It was promulgated on 28 July; the main new rules have applied since 29 July 2026.

The GModG is the renamed and restructured Building Energy Act. The key change for owners: the blanket 65 per cent requirement has been scrapped without replacement. The choice of heating technology lies with the owners again — heat pump, district heating, biomass, hybrid, or a new gas or oil boiler.

In its place, the bio-fuel staircase (Bio-Treppe, § 43 GModG) applies to new fossil-fuel systems. Anyone who installs a gas, oil or LPG heating system after 29 July 2026 must, from 2029, use a rising share of climate-friendly fuels such as biomethane, bio-oil or hydrogen:

New heating law (GModG) in force

since 29 July 2026

Bio-fuel staircase from 1 January 2029

at least 10%

from 1 January 2030

at least 15%

from 1 January 2035

at least 30%

from 1 January 2040

at least 60%

Systems installed before 29 July 2026

not affected

For a WEG, this means: a new gas boiler is legally possible again, but not as cheap as the quoted price suggests. Biomethane costs considerably more than natural gas, and the required share rises to 60 per cent over the life of the system. Buying a boiler for twenty years today means buying into that price trend. Funding for climate-friendly heating (BEG) continues with adjustments, according to the federal government; the funding rates are due to fall gradually from 2027. If you have to replace anyway, check the current position before planning.

What Nuremberg’s heat plan still means

The Heat Planning Act (WPG) requires municipalities with more than 100,000 inhabitants to present a municipal heat plan by 30 June 2026; smaller municipalities have until mid-2028. Nuremberg finished early: the city council adopted its heat plan on 4 June 2025, drawn up together with the utility N-ERGIE (information from the City of Nuremberg).

With the 65 per cent rule gone, the heat plan no longer triggers any installation deadline. That does not make it worthless — quite the opposite. It is now the most important decision aid for the question of which technology will work at a given location in the long term.

The heat plan divides the city into supply areas. In densely built-up areas, especially in the centre, the district heating network is to be expanded and densified; district heating currently covers around a quarter of Nuremberg’s heating demand. In less dense areas, decentralised solutions such as heat pumps become more important.

This is strategic planning, not a promise. Being designated a future district heating area does not give you a right to a connection by any particular date. For a WEG whose boiler will be due in three years, the decisive question is therefore not what the plan foresees but what the network operator commits to for the specific address and the specific period. That information should be in writing before the owners decide.

For properties in Fürth, Erlangen and the surrounding municipalities, check the respective municipality — some have not yet completed their heat planning.

The decision in the owners’ association

The heating system is part of the common property. The owners decide on replacing it, not the property manager — WEG management prepares the resolution and implements it.

Maintenance or structural alteration? Replacing an existing system with a new one that does the same job is maintenance — a simple majority of the votes cast is enough, and there is no quorum. If noticeably more is added, for example a district heating connection with a transfer station where there used to be a boiler, or a heat pump that involves work on the façade and outdoor areas, it can be a structural alteration under § 20 WEG. The cost rules of § 21 WEG then apply — what that means is explained in our article on structural alterations. Settle this distinction before the meeting, not in the argument afterwards.

Cost allocation for maintenance follows the community rules (Gemeinschaftsordnung), unless the owners have resolved otherwise. A different allocation key for individual costs is possible under § 16(2) WEG, but must be expressly resolved.

The choice of technology is once again a genuine trade-off for the owners. That is exactly why the resolution needs a cost-effectiveness calculation that includes the bio-fuel staircase and rising CO₂ prices — otherwise the quote with the lowest installation price wins at the meeting, not the one with the lowest costs over twenty years.

A realistic timeline

Financing: reserve, special levy or loan

If the maintenance reserve (Erhaltungsrücklage) is enough, it is simple: resolve on the withdrawal and show it separately in the annual statement. In most associations it is not enough. Whether your reserve matches the need is shown by the maintenance reserve calculator.

Then a special levy (Sonderumlage) and a loan to the association are the two options. The special levy is quicker and cheaper but hits everyone at once and causes liquidity problems for some owners — which the others then help to carry. The loan spreads the burden, costs interest and requires a carefully worded resolution, because the owners are liable to creditors in proportion to their co-ownership shares (§ 9a(4) WEG).

For owners who let their flat, a modernisation rent increase under § 559 BGB may be possible if the work goes beyond mere maintenance. The share attributable to maintenance must be deducted — and the association’s accounts must make exactly that split possible. With the GModG, the legislator has also split the running costs of new fossil-fuel heating between tenant and landlord (§§ 5a ff. CO2KostAufG): for gas, oil and LPG systems installed after 29 July 2026, the landlord bears half of the CO₂ costs and gas network charges from 2028, and from 2029 half of the extra costs for the bio share, capped at 30 per cent of the fuel. In an association with many letting owners, that shifts the calculation significantly: for them, a new gas boiler is more expensive than its running costs suggest. Have a planned rent increase checked in advance.

The most common mistake

Starting too late. A WEG whose boiler fails in January has no time for specialist planning, comparing quotes, a funding application and a properly convened owners’ meeting. It makes a makeshift repair or, under pressure, resolves on the option with the lowest installation price — which under the new law is no longer automatically the cheapest. If you track the system’s remaining life in a maintenance plan, you have this discussion three years before it fails. The plan, tendering and checking quotes are part of technical management.

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For the associations it manages, Ravenica keeps a maintenance plan with remaining useful lives and supports maintenance work from specialist planning through to acceptance.