GEG 2026: Which Heating System Is Mandatory When Buying a House?
What buyers need to know about Germany's Building Energy Act, the 65% rule, and municipal heat planning
Minimum RE share
65%
For every newly installed heater
Deadline — large cities
30 Jun 2026
Mannheim, Heidelberg, Ludwigshafen
Deadline — municipalities
30 Jun 2028
Schwetzingen, Speyer, Hockenheim …
Max. KfW grant
up to 70%
With replacement + income bonus
Key takeaways
TL;DR
Since 2024: Every newly installed heating system in Germany must run on at least 65 percent renewable energy. For existing buildings, the rule applies only once the municipality has completed its heat plan – by 30 June 2026 for cities over 100,000 inhabitants, and by 30 June 2028 for smaller municipalities. Existing oil and gas heaters may continue to operate and be repaired. All fossil-fuel-only heating systems must be phased out by 2045.
Existing oil and gas heaters may continue to run after purchase — the 30-year rule matters, not the purchase date.
The 65% rule applies to existing buildings only after the municipal heat plan is in force (2026 or 2028).
Heat pumps are the most common GEG-compliant solution — effectively from €8,000 net after KfW subsidy.
From 1 January 2045, pure oil and gas heating is fully banned in Germany.
What does GEG 2026 regulate?
The Building Energy Act (Gebäudeenergiegesetz, GEG) – colloquially the „heating law" – has been in force since 1 January 2024 and remains the central framework for installing new heating systems in Germany in 2026. At its core is the 65 percent rule: every newly installed heating system must be powered by at least 65 percent renewable energy.
For buyers of existing homes, the key point is: the obligation does not kick in automatically upon purchase. It applies only when a heating system is replaced or newly installed – and only once the municipality has finalised its binding heat plan.
Which deadlines apply in which city?
For buyers in the Rhine-Neckar region: cities like Heidelberg, Mannheim and Ludwigshafen (all above 100,000 inhabitants) must publish their municipal heat plan by 30 June 2026. For smaller municipalities such as Schwetzingen, Speyer, Weinheim or Hockenheim the deadline is 30 June 2028.
| Municipality size | Heat-plan deadline | When does the 65% rule apply to replacements? |
|---|---|---|
| Over 100,000 inhabitants (e.g. Mannheim, Heidelberg, Ludwigshafen) | 30 June 2026 | After local decision, at the latest 1 July 2026 |
| Under 100,000 inhabitants (e.g. Schwetzingen, Speyer, Hockenheim) | 30 June 2028 | After local decision, at the latest 1 July 2028 |
| New build developments (anywhere in Germany) | Already since 1 January 2024 | Immediately on installation |
Which heating systems meet the 65% rule?
| Heating system | Meets 65% rule? | Typical investment, single-family home |
|---|---|---|
| Heat pump (air-to-water, brine-to-water) | Yes – automatically | €24,000 – €40,000 |
| District heating connection | Yes – automatically | €8,000 – €15,000 connection |
| Hybrid heating (gas + heat pump) | Yes, with certificate | €28,000 – €45,000 |
| Biomass boiler (pellets, wood) | Yes – in existing buildings | €22,000 – €32,000 |
| Solar thermal hybrid | Yes, with certificate (min. 65% RE) | €25,000 – €38,000 |
| Direct electric (infrared) | Only in very well-insulated homes | €8,000 – €15,000 |
| Gas boiler with 65% biomethane/H2-ready | Yes, with mandatory supply guarantee | €15,000 – €22,000 |
| Pure oil or gas boiler (new) | No – only as emergency repair, time-limited | — |
What does GEG mean concretely when buying a house?
- 1Heating is functional and less than 30 years old: it may continue to run, be serviced and repaired – even oil and gas systems.
- 2Heating is older than 30 years (constant-temperature boiler, installed before 1996): a general replacement obligation applies. This predates the GEG.
- 3Heating fails after purchase: transitional rules apply – you have up to 5 years to install a GEG-compliant system. A used fossil-fuel boiler may be used temporarily.
Which subsidies apply in 2026?
| Bonus component | Subsidy | Condition |
|---|---|---|
| Base grant | 30% | Installation of a GEG-compliant heating system |
| Climate-speed bonus | 20% | Replacing a functional oil/gas system by 31 Dec 2028 |
| Income bonus | 30% | Taxable household income < €40,000 p.a. |
| Efficiency bonus (heat pump) | 5% | Natural refrigerant or geothermal |
| Max. combined grant | 70% | Income threshold + replacement of old system |
Next steps for buyers
- Confirm the heating system's age before signing (plaque, chimney-sweep invoice)
- Check the target city's heat plan – town hall or municipal utility
- Review the Energy Performance Certificate (Bedarfsausweis preferred)
- Commission an individual renovation roadmap (iSFP) – adds 5% BEG bonus
- Budget financing early, including renovation reserve
Frequently asked questions
Answers to the most important questions from our clients about GEG, heating replacements and buying a house in the Rhine-Neckar region.
Planning to buy in Schwetzingen or the Rhine-Neckar region?
We check for free which heating system your target property uses, which deadlines apply in the target city and how that affects the purchase price. Includes financing planning with a renovation budget.
