Composite: REFIRE, Depositphotos.com, Lisa Glanz
The average German residential dwelling sits at energy efficiency Class D. That is the midpoint of an eight-class scale that now has direct and measurable consequences for property values. According to Immowelt's analysis of 2025 listings, apartments with the best rating — Class A+ — command prices around 20% higher than comparable Class D properties. At the other end, Class H houses trade at a discount of around 17%. The brown discount is no longer a regulatory abstraction. It is priced into the market.
A Wüest Partner study, based on 1.38 million data points from mid-2023 to mid-2025, puts precise figures on the gradient. Each step down the energy efficiency scale reduces residential rents by an average of €0.22 per square metre and purchase prices by €107–118 per square metre. A Berlin-specific analysis of 766 multi-family dwelling transactions between 2022 and 2025 found that every additional kilogram of CO2 emitted per square metre per year reduces the transaction price by approximately €2 per square metre. "ESG quality has become a permanent, data-based factor in pricing," the study concludes.
CBRE's analysis of 2.1 million residential units confirms the structural scale of the challenge. The average German dwelling consumes 124 kWh per square metre per year — Class D. Regional disparities are significant: in northern and western Germany, more than 50% of buildings fall into Class E or below, compared to under 30% in eastern and southern regions, partly reflecting differences in district heating connectivity and modernisation history. "Inefficient properties are steadily losing value and generating significantly higher operating costs," says Dr. Thorsten Huff, Senior Director for ESG and Sustainability Solutions at CBRE.
What sits behind these price effects is not only current energy consumption, but expected expenditure. Buyers are no longer pricing what a building costs to run today, but what it will cost to bring it up to standard. Part of the discount applied to inefficient stock is therefore a discount for capital that has yet to be spent.
What regulation requires - and when
The European Energy Performance of Buildings Directive 2024 sets binding reduction targets: a 16% cut in national average consumption by 2030 and 20–22% by 2035, with 55% of those savings to come from the worst-performing buildings. Carbon pricing adds further pressure — Germany's national CO2 levy is rising, and ETS2, the EU's expanded emissions trading system covering buildings, is on its way. Under existing rules, landlords of the least efficient properties already bear a growing share of carbon costs directly.
Germany's new government is reforming the Building Energy Act (GEG) under the banner of "technology neutrality" — replacing the previous administration's prescriptive heat pump requirements with a focus on measurable CO2 reductions. The physics, however, remain unchanged. As Werner Ottilinger of Sauter Germany puts it: "Energy efficiency must go up, otherwise the value of the building goes down." Huff at CBRE is direct about the medium-term trajectory: Classes G and H will become increasingly difficult to operate economically in many urban markets as the cost burden on landlords rises.
Berlin’s latest legislative push illustrates the tension. The proposed simplifications to building regulations are intended to accelerate housing delivery by lowering certain technical requirements, particularly for conversions. At the same time, the city is targeting the worst-performing buildings for improvement and backing refurbishment with a €5–10bn support fund. The implication is clear: even where standards are eased to support supply, the cost of improving energy performance does not disappear — it may be shifted, shared or deferred, but ultimately must still be borne by owners and investors.
The upgrade calculus
Not every upgrade requires a full retrofit. Ottilinger argues that building automation — replacing mechanical thermostats with smart multi-sensor control systems that manage heating, cooling, ventilation and lighting in real time — can reduce energy consumption by up to 20% at significantly lower cost and CO2 footprint than demolition and rebuild. For properties in Classes D, E and F, this approach can move the needle on efficiency class, operating costs and market value without the disruption of structural works. "The value of many existing buildings is higher than it seems — because they can be made competitive on the market again with relatively little effort," he says.
But the economics are not uniform. The price data suggests that moving a building out of the weakest efficiency classes can preserve or recover value. The case for pushing further — towards top-tier efficiency standards — is more dependent on location, rental potential and financing conditions. In stronger markets, the premium for efficient stock can justify deeper intervention. In weaker locations, the same investment risks overshooting what the market will pay.
Wüest Partner's Dr. Michael Heigl states that "energy-efficient renovations already represent a robust business case today" — a claim supported by the observed price premiums. For multi-family houses, the study records price effects of up to 36% between best and worst efficiency classes. But those premiums are not evenly distributed, and they do not automatically translate into a positive return on every retrofit.
The risk, increasingly, is polarisation. A large share of Germany’s residential stock sits in the middle efficiency bands — Classes D, E and F — where incremental improvements are both technically feasible and economically defensible. At the lower end, however, the combination of weak energy performance, rising regulatory pressure and limited rental growth creates a more difficult equation. In such cases, the cost of compliance begins to compete directly with the underlying value of the asset.
For investors, the trajectory is clear and the price signals are already visible. Properties that cannot reach viable efficiency levels face a widening discount and a growing cost burden. Those that can be upgraded — whether through automation, targeted refurbishment or more comprehensive renovation — are demonstrating stronger price resilience and faster recovery from recent market dislocation. The question is no longer whether energy efficiency affects value. It is whether the upgrade economics work at asset level, in a given location, under current financing conditions. That calculation is becoming more immediate as transactions resume.