⚡ In brief: The GModG has been in force since July 29, 2026. The 65% renewable energy requirement for heating replacement is dropped. Instead, a "bio-ladder" starts in 2029 — a gradually increasing blending obligation for climate-friendly fuels (10% → 60% by 2040). There is no renovation mandate for residential buildings. Some provisions (energy certificate, primary energy factor) only phase in from 2027.
🆕 Update (July 31, 2026): The GModG was promulgated in the Federal Law Gazette on July 28, 2026 (BGBl. 2026 No. 226) and took effect on July 29, 2026. The core rules (removal of the 65% requirement, bio-ladder, free heating choice) apply immediately; the EPBD transposition (new energy certificate requirements, lowered primary energy factor, renovation duties for non-residential buildings) phases in from January 1, 2027.
What Is the GModG?
The Building Modernisation Act (GModG) fully replaces the current Building Energy Act (GEG). On February 24, 2026, the coalition factions agreed on key points, the draft bill followed on May 5, 2026. On May 13, 2026, the federal cabinet approved the draft law.
The law transposes the EU Energy Performance of Buildings Directive (EPBD) into German law. After the Bundestag and Bundesrat, it was promulgated in the Federal Law Gazette on July 28, 2026 and took effect on July 29, 2026. It enters into force in stages: the heating-related core rules have applied since July 29, the EPBD transposition (including energy certificate requirements, primary energy factors, renovation duties for non-residential buildings) from January 1, 2027, with further stages in 2028 and 2030. New from the process: a hardship provision for landlords in the CO₂ cost allocation.
The Key Changes
1. Free Heating Choice — 65% Rule Dropped
The previous requirement that new heating systems must use at least 65% renewable energy is eliminated. Homeowners can freely choose: heat pump, gas, oil, district heating, hybrid systems, or biomass. The mandatory replacement of oil and gas heaters older than 30 years is also dropped.
2. Bio-Ladder from 2029
Anyone installing a new fossil heating system must blend in climate-friendly fuels from 2029 — biomethane, bio-heating oil, or synthetic fuels. The steps at a glance:
Alternatively, the blending obligation can also be met until the end of 2034 by installing a hybrid heat pump or using solar thermal energy.
3. New Tenant Protection
To protect tenants from high heating costs due to the bio-ladder, from 2028: if a landlord installs a fossil heating system, they must cover half of the CO₂ levies and the biogas blending costs. A hardship provision is planned for unrenovated buildings with low rents.
4. Energy Certificate: New A-to-G Scale
From January 1, 2027, the previous German scale is replaced by an EU-wide system with classes A to G. Class A represents zero-emission buildings, class G the worst-performing buildings in the stock. Previously issued certificates remain valid for their full 10-year term.
5. Extended Certificate Requirements
Also from 2027, new mandatory details are added (including life-cycle greenhouse gas emissions and low-temperature readiness), and the energy certificate will be required for lease renewals and major renovations (more than 25% of the building envelope) — not just for sale and new rentals as before. Fines of up to €10,000 apply for missing certificates.
6. Primary Energy Factor for Electricity Lowered
From January 1, 2027, the primary energy factor for electricity drops from 1.8 to 1.5. This improves the calculated rating of heat pumps and other electricity-based heating systems in energy certificates.
7. Zero-Emission Standard for New Buildings from 2030
From 2030, all new buildings must meet the zero-emission standard. For public non-residential buildings, this applies from 2028.
8. No Renovation Mandate for Residential Buildings
The often-feared renovation mandate for existing residential buildings is not coming. For non-residential buildings, however: the worst-performing 16% must be modernized by 2030, the worst 26% by 2033.
What Does This Mean for Your Renovation?
Energy Consulting Becomes More Important
More technology openness means more freedom of choice — but also more need for advice. Independent energy consulting helps you find the most economical long-term solution.
iSFP Becomes EU Renovation Passport
The individual renovation roadmap (iSFP) will likely be developed into an EU-compliant renovation passport. The 5% iSFP bonus for BEG funding continues — though since the BEG reform of July 21, 2026 it only applies above an eligible minimum investment volume of €30,000.
Heat Pumps Benefit Twice
The lowered primary energy factor (1.5 instead of 1.8) improves heat pump ratings in energy certificates. The 30% BEG base subsidy remains in place; since the BEG reform of July 21, 2026, the climate speed bonus is 16%, drops by 4 percentage points every six months from February 2027, and expires from August 2028.
Caution with Fossil Heating
Even though fossil heating is allowed again: Rising CO₂ levies, the bio-ladder, and potential network charge increases will make oil and gas more expensive long-term. Landlords must also cover half of these additional costs. Anyone investing now should calculate operating costs over 15–20 years.
Timeline
Coalition key points agreed
Draft bill published
Bundestag and Bundesrat pass the GModG
Promulgation in the Federal Law Gazette (BGBl. 2026 No. 226), core rules take effect
EPBD stage: new energy certificate requirements, electricity primary energy factor 1.5, non-residential renovation duties
CO₂ and bio-ladder costs split 50/50 between tenant and landlord
Bio-ladder starts (10% blending obligation)
Zero-emission standard for all new buildings
Bio-ladder rises to 30%
Bio-ladder reaches 60%
Note: The GModG took effect on July 29, 2026 (promulgated July 28, 2026, BGBl. 2026 No. 226); several provisions phase in from 2027, 2028, and 2030. This article does not replace individual consulting.
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