The energy condition of a property is no longer a marginal issue, but a decisive price factor. Between the best and worst energy standards, asking prices for houses now differ by around 30 percentage points. The Energy Performance Certificate, energy efficiency class and type of heating now help determine how quickly and at what price you can sell. We show you how the energy factor will influence property values in 2026, which obligations the German Building Energy Act prescribes and what buyers pay particular attention to.
Why energy efficiency determines value
Just a few years ago, the energy balance played a secondary role when purchasing a property. That has fundamentally changed. High energy prices, the carbon pricing of fossil fuels and the requirements of the German Building Energy Act (GEG) have turned energy consumption into a fixed calculation factor. Buyers today calculate not only the purchase price, but also the expected heating and renovation costs for the coming years.
Experts speak of a Green Premium for efficient properties and a Brown Discount for properties requiring renovation: Low energy demand is rewarded with a premium, while high consumption is penalized with a discount. Financing reinforces the effect: Banks assess unrenovated properties more cautiously, and low-interest subsidized loans increasingly depend on the efficiency standard achieved. Energy efficiency therefore has a dual impact – on the achievable price and on marketability.
Energy efficiency classes from A+ to H: the price effect in figures
The Energy Performance Certificate assigns every residential building an energy efficiency class – from A+ (very low demand, under 30 kWh per square metre per year) to H (over 250 kWh per square metre per year). This letter scale has become a quick benchmark for comparison among buyers.
A nationwide price analysis by immowelt from spring 2025 shows how strongly the class affects the price:
- Houses in class A+ are offered at an average of 16 percent higher prices than comparable houses with a medium standard (class D).
- Condominiums in classes A+ and A achieve even a premium of 23 percent compared with Class D.
- At the lower end of the scale, houses in the worst Class H are around 14 percent cheaper than properties in Class D.
- For apartments, the discount for Class H is lower at around 4 percent – location and layout often carry more weight here.
For houses, the gap between the best and worst standard therefore adds up to around 30 percentage points. Important to know: As part of the EU Buildings Directive, the scale will be standardized across Europe in the medium term. Energy performance certificates already issued remain valid, but the class remains the central value lever.
Which factors shape a property's energy rating
The energy efficiency class is the result of several building components. The following points are particularly decisive for the assessment:
- Type and age of heating system: Heat pumps, district heating or a modern hybrid solution increase value. An old oil or gas heating system, by contrast, signals impending replacement costs.
- Insulation of the roof, façade and basement ceiling: It determines the largest portion of heat loss and thus the final energy demand.
- Windows and glazing: Single or old insulating glazing noticeably increases the rating value.
- Hot water generation and ventilation: Efficient systems and controlled ventilation improve the balance.
- Energy sources: The share of renewable energy in heating demand is gaining importance for buyers and banks.
The interaction is decisive: A new heating system in an uninsulated house only improves the class to a limited extent. For the question of value, the overall condition matters, which the energy performance certificate consolidates into a single rating value.
The energy performance certificate: mandatory and a value signal when selling
When selling, the energy performance certificate is not optional. It must be presented no later than during the viewing and handed over to the purchaser after the purchase (§ 80 GEG). Mandatory information is already required in the property advertisement (§ 87 GEG): the type of certificate, the final energy demand or consumption, the main energy source for heating, and – for residential buildings – the year of construction and energy efficiency class.
There are two variants (§ 79 GEG):
- The consumption-based certificate is based on actual energy consumption over the past few years. It is inexpensive, but depends heavily on heating behavior the previous occupant.
- The consumption-based energy certificate calculates consumption based on the previous occupants’ energy usage. The demand-based certificate calculates energy demand based on the building structure, insulation and systems technology. It is more meaningful and more reliable for buyers.
Every energy certificate is valid for ten years (Section 79 GEG). For residential buildings with up to four apartments, whose building application was submitted before 1 November 1977 and which have not been energetically modernized since then, a demand-based certificate is mandatory. If the certificate is missing when the property is sold or contains incorrect information, fines of up to 10,000 euros may be imposed. For a sale, the following applies: A current, properly prepared demand-based certificate with a good rating is a selling point – a missing or poor certificate invites renegotiation.
Heating, GEG and renovation requirements: the buyer’s perspective
No building component currently affects value as much as the heating system. The GEG requires newly installed heating systems to use at least 65 percent renewable energy. In new development areas, this has applied since 1 January 2024; in existing buildings and outside new development areas, the requirement is linked to municipal heating plans – in cities with more than 100,000 inhabitants, it takes effect after 30 June 2026, and in smaller municipalities after 30 June 2028 (see the federal GEG information portal).
There is also a ban on operating old boilers (Section 72 GEG): Oil- and gas-fired boilers that operate at a constant temperature and are more than 30 years old may no longer be operated. Exemptions apply to modern condensing and low-temperature boilers, as well as owners who have lived in their one- or two-family home themselves since February 2002. Heating systems may only run on fossil fuels until the end of 2044 in any case.
For buyers, this means that an old fossil-fuel heating system is a foreseeable cost item that they will take into account in the price. This is precisely where the largest part of the brown discount arises. Conversely, sellers should be aware that the legislature is working on a reform intended to loosen the rigid 65-percent requirement and once again give owners more choice regarding the type of heating system. The fundamental trend – efficiency beats inefficiency – remains unaffected.
Advantages and disadvantages of upgrading energy efficiency before the sale
Whether renovation before the sale is worthwhile depends depends on the individual case. You should weigh these points:
- Advantage – higher price: Moving up one class can significantly increase the achievable price and speed up the sale.
- Advantage – larger group of buyers: Efficient properties are easier to finance and appeal to more prospective buyers.
- Advantage – less renegotiation: A good energy certificate takes away buyers’ strongest argument for price reductions.
- Disadvantage – high upfront investment: Insulation or replacing the heating system can cost five-figure sums, which do not always translate fully into the price.
- Disadvantage – time and effort: Renovations delay the sale by months and tie up capital.
- Alternative – sell honestly: It is often more sensible to disclose the need for renovation transparently and set a realistic price rather than invest yourself.
FAQ on Energy Certificates and Property Value
Which energy efficiency class is considered good?
Classes A+ to C are considered good. Starting with class E, many buyers become concerned about renovation costs; from F and G onward, price reductions clearly move into the foreground. The middle class D is often used as a benchmark in market analyses.
Do I have to carry out energy renovations before selling?
No. There is no legal obligation to renovate solely because of a sale. Whether an upgrade is worthwhile is purely a cost-effectiveness calculation: Is the move up a class proportionate to the costs and effort? In many cases, selling transparently in its current condition is the wiser choice.
Consumption-based or demand-based certificate – which is mandatory?
For most existing buildings, you may choose between the two. However, a demand-based certificate is mandatory for residential buildings with up to four apartments whose building application was submitted before November 1, 1977, and which have not been energetically modernized since then. For valuation purposes, the demand-based certificate is generally the more reliable choice.
How much does an energy certificate cost?
A consumption-based certificate for a single-family home costs approximately 50 to 120 euros, depending on the provider. A demand-based certificate is considerably more expensive at around 300 to 500 euros because it requires a precise assessment of the building fabric. Costs are higher for apartment buildings.
Are there penalties if the energy certificate is missing?
Yes. Anyone who fails to present a valid energy certificate when selling, omits the mandatory information in the advertisement, or provides incorrect figures commits an administrative offense. This can be punished with a fine of up to be penalized by 10,000 euros.
Does an old heating system reduce the value of a property?
Generally, yes. Buyers factor in the foreseeable replacement of an old oil or gas heating system, including any possible insulation work, and deduct these costs from the price. Conversely, a modern heating system based on renewable energies increases the value.
Conclusion: The energy factor belongs in every pricing strategy
The energy performance certificate and the energy condition will be key value drivers in 2026—not merely a formality. The energy efficiency class translates the condition of the building into a benchmark that determines whether there is a premium or discount, and the heating issue has become the most important individual factor. Sellers should have the energy performance certificate ready at an early stage, correctly and with the required information, honestly identify the need for renovation, and align the price accordingly. This way, you can avoid unpleasant surprises during negotiations—and use a good energy standard for what it is today: a genuine selling point.