New heating law: what plumbing and heating sites must update

The Bundestag passed the new rules on 10 July 2026 (BBSR). The amending act appears in the Federal Law Gazette as BGBl. 2026 I No. 226 of 28 July 2026 (BBSR), and its articles do not take effect all at once but in stages. The first stage concerns exactly the topic heating businesses discuss on the phone every day: replacing a heating system. It has applied since 29 July 2026 (BBSR). At the same time the act got a new name. The Building Energy Act, GEG for short, has become the “Gesetz zur Einsparung von Energie und zur Modernisierung der Wärmeversorgung in Gebäuden”, known as the Building Modernisation Act or GModG. If your website links to the statute on Gesetze im Internet, the link still lands on the right page, because the address has stayed the same. The name in the link text, however, is no longer correct.

This removes three statements that have appeared on many heating pages in recent years. A new heating system no longer has to prove a fixed share of renewable energy across the board. No mandatory advice is required before installing a gas or oil boiler. And the operating bans that forced certain old boilers to be switched off no longer apply. In the consolidated version of the GModG on Gesetze im Internet, §§ 71, 72 and 73 have since been marked as “weggefallen” (repealed), and the statute contains neither the 65 per cent requirement nor an advice obligation before a heating system is installed.

What is new is the structure. § 42 GModG lists ten options for replacing a heating system (§ 42(2) GModG): heating with gas, heating oil or liquefied gas, the electrically driven heat pump, the solar thermal system, biomass or hydrogen, the heat pump hybrid, the solar thermal hybrid, high-efficiency combined heat and power, direct electric heating, the substation for a heat network and other innovative heating solutions. Once the owner chooses one of them, the requirements of §§ 43 to 46 apply. For the website, this is the most important shift: there is no longer a quota every new heating system has to meet, but requirements that depend on the chosen technology.

The table also shows what stays. The duty to inspect heating systems in larger apartment buildings remains in § 60b, with the same deadlines and building size. If your maintenance page promotes this inspection, the main change there is the name of the act. A separate section further down covers it, because this duty is one of the few that can be stated with a fixed date.

The following phrases appear in variations on many heating pages. Each of them was defensible under the old law and is now wholly or partly wrong. The references to the old law refer to the version of the GEG that applied until 28 July 2026.

Not every old statement has become wrong. The heat pump remains one of the options, and the inspection duties for heating in larger residential buildings continue. Funding also remains a topic: the GModG still contains its own part on financial support, and the amending act brings consequential changes there (BBSR). On most pages, what is wrong is not the product being promoted but the justification, the obligation it was sold with. How a trade presents itself on the website as a whole is described in the article on websites for plumbing and heating.

The new copy follows three rules. First: describe options instead of claiming obligations. The customer decides which technology to install; the page explains what each option involves. Second: every legal statement gets a visible date stamp and a legal reference, so that customer and business can later see what it refers to. Third: anything that depends on the building belongs in the conversation, not in a blanket sentence. A sample paragraph for the heating page could read like this:

The paragraph contains no percentages, no years other than the date stamp and no funding amount. That is deliberate: it stays correct as long as the act applies on this point, and it refers everything building-specific to the conversation. If you want to show the bio ladder in detail, add it below as a separate table with its legal reference:

The table needs a sentence that puts it in context: it applies to heating with gas, heating oil or liquefied gas newly installed in an existing building after 29 July 2026, and the obligation falls on the owner of the building, or on the operator of the system where the owner does not run it (§ 43(1) and (6) GModG). Instead of the fuel shares, the act also allows other routes under certain conditions, such as a solar thermal system or a ventilation system with heat recovery (§ 43(3) and (4) GModG). A heat pump hybrid meets the requirement if, at part-load point A under DIN EN 14825, the heat pump reaches at least 30 per cent of the output of the peak-load generator in bivalent parallel or partly parallel operation, or at least 40 per cent in bivalent alternative operation (§ 43(5) GModG). Thresholds like these belong on a specialist page for hybrid systems, not in the introduction on the home page. For systems installed before 29 July 2026, the legal position has to be clarified case by case; a blanket sentence on the website does not help there.

The emergency service page has its own rule. If a heating system running on gas, heating oil or liquefied gas is newly installed in 2028 because the old system failed beyond repair, the obligation under § 43(1) only applies after twelve months from installation (§ 43(7) GModG). If your emergency page promotes quick replacement, include this point in the advice after the call-out instead of announcing an obligation or an exemption across the board. How the emergency page itself is built is covered in the article on presenting your emergency service online.

In recent years many heat pump pages argued with the law: if you have to prove 65 per cent renewable energy anyway, there is hardly a way around the heat pump. This argument no longer holds since 29 July 2026 (BBSR). What remains are the reasons that do not depend on the law: running costs, independence from fuel deliveries, the combination with a photovoltaic system, the space freed up in the basement. These reasons depend on the building and on energy prices, and they can be shown with examples from your own projects without an obligation having to carry them.

One obligation remains for heat pumps in larger buildings. Heat pumps installed after 31 December 2023 in a building with at least six flats or other independent units must undergo an operational inspection after a full heating period, at the latest two years after commissioning; domestic hot water and air-to-air heat pumps are exempt (§ 60a(1) GModG). The inspection must be carried out by a qualified person who has successfully completed training in inspecting heat pumps; the act expressly names plumbers and heating engineers as qualified (§ 60a(3) and (4) GModG). For businesses working for property managers and landlords, this is a service with a firm legal basis that belongs on the maintenance page.

Heating law did not settle down on 29 July. The BBSR expressly gives the current consolidated reading version a validity period until 31 December 2026 (BBSR). From 1 January 2027 the next stage follows with requirements from the European buildings directive, including a phased solar obligation for new residential and non-residential buildings (BBSR). By 1 December 2026 the federal government is to present the law on the green gas and green heating oil quota (§ 42a GModG), and an evaluation of the act is laid down for 2030 (BBSR). Each of these stages can affect copy on a heating business website.

A visible date stamp does not protect against every change, but it makes the statement honest: it tells the customer which point in time it refers to, and it tells the business which copy to check at the next change. In practice this means putting legal statements into separate text blocks maintained in one place instead of repeating the same sentence on five pages. How content can be spread across several service pages without being duplicated is shown in the article on service pages instead of one combined page. And why content ages faster than the technology underneath is described in the article on maintaining the site after handover.

One rule of thumb helps with classifying: if a sentence contains an obligation, a deadline or a percentage, it belongs in the first group until proven otherwise. If it describes a technology, its benefits or how the business works, the law usually does not affect it. Deleting archive articles is rarely necessary. If they no longer bring visitors and consist only of the old law, redirect their address to the current page so that external links do not lead nowhere; the article on relaunching without losing visibility explains why.

For most businesses the revision is not a new website but copy maintenance in a handful of places. Small text and image changes of up to half an hour a month are included in our website maintenance from 49 euros per month net, cancellable monthly, with no minimum term, prices as of September 2026. If several heating pages, FAQs and downloads are affected, we quote the revision in advance. If the website is old enough that structure and technology should be renewed anyway, a relaunch starts at 2,900 euros net and a new website at a fixed price starts at 1,490 euros net; the pricing overview has the details. How a website for your trade can be structured is shown on the page on web design for plumbing and heating.