If you are looking for a flat in Germany, listings often show figures such as the energy efficiency class or the final energy demand. These details are not optional. The Building Energy Act (Gebäudeenergiegesetz, GEG) requires them in property listings as soon as an energy certificate exists. This guide explains which mandatory details exist and what you can read from them when you decide.
Short answer: Under section 87 GEG, property listings in commercial media for sale, letting or leasing must contain certain details from the energy certificate, provided that a certificate exists. These include the type of certificate, the final energy demand or consumption, the main heating energy sources and, for residential buildings, the year of construction and the energy efficiency class. Last updated: November 2026, version shown on the statute page.
The most important points in brief
- The duty applies to property listings in commercial media as soon as an energy certificate exists.
- Responsible parties are sellers, landlords, lessors, lessors under leasing arrangements or brokers, insofar as they are responsible for the publication.
- Mandatory details are the type of certificate, the final energy demand or consumption, the heating energy sources and, for residential buildings, the year of construction and the efficiency class.
- For non-residential buildings, heat and electricity must be stated separately.
- Older certificates are covered by transitional rules under section 87 (3) GEG, which refers to section 112.
Which details must appear in the listing?
The provision distinguishes between two types of energy certificate. The energy demand certificate under section 81 GEG and the energy consumption certificate under section 82 GEG differ in the basis of their figures. Under section 87 (1) no. 1 GEG, the listing must state which type exists. The table gives an overview of the mandatory details.
| Detail | Applies to | Provision |
|---|---|---|
| Type of certificate (demand or consumption) | all buildings | Section 87 (1) no. 1 GEG |
| Final energy demand or final energy consumption | all buildings | Section 87 (1) no. 2 GEG |
| Main energy sources of the heating | all buildings | Section 87 (1) no. 3 GEG |
| Year of construction | residential buildings | Section 87 (1) no. 4 GEG |
| Energy efficiency class | residential buildings | Section 87 (1) no. 5 GEG |
| Heat and electricity stated separately | non-residential buildings | Section 87 (2) GEG |
The term commercial media is named explicitly in the statute. Whether a particular portal or newspaper falls under it has to be judged case by case. Anyone who sees a listing without the mandatory details should therefore not assume it is complete.
How do you read the figures correctly?
The final energy demand is usually given in kilowatt hours per square metre and year. The figure therefore describes the energy input in relation to the area and says nothing about the price. A single value is only partly meaningful, especially when comparing flats in different buildings.
Assumption: the flat has 70 square metres of living space, and the final energy demand is 120 kilowatt hours per square metre and year. This gives 8,400 kilowatt hours per year. The calculation shows only the quantity, not the cost.
- Calculate the quantity: 70 square metres times 120 kilowatt hours gives 8,400 kilowatt hours per year (assumption).
- Calculate the cost: the euro amount requires the current unit price of your supplier, which the certificate does not contain.
- Compare: the figure becomes meaningful only when flats of similar size and similar use are compared.
What does the energy efficiency class mean for you?
The energy efficiency class is a letter-based classification. It makes a quick comparison easier but does not replace the question of the actual heating cost burden. A building with a good class can prove expensive in practice if use and consumption are high, and the reverse also applies. The class should therefore be read together with the year of construction, the heating system and the past service charge statement.
What to do if details are missing?
The duty applies regardless of how a provider implements it. Whether a listing meets it can be checked against the statute. As a prospective tenant, you can ask the provider in writing for the missing details and ask to see the energy certificate. How the provider responds remains a matter of negotiation. For legal steps against a listing, advice is worthwhile.
Frequently asked questions
Must every listing show an energy certificate?
No. The duty applies only when an energy certificate exists and the listing appears in commercial media. Then the mandatory details must be included, but the certificate itself does not have to be printed.
What is the difference between a demand certificate and a consumption certificate?
The energy demand certificate under section 81 GEG and the energy consumption certificate under section 82 GEG differ in the basis of their figures. The listing must state which type exists, so that you can interpret the values correctly.
Does the duty also apply to student halls of residence?
The statute refers to sale, letting, leasing and leasing arrangements of buildings or flats. Whether a particular hall of residence offer falls under it depends on its structure and should be asked of the provider.
Do I have to read the energy certificate myself?
You do not have to, but it is worthwhile. The mandatory details in a listing show only an extract. If you ask to see the certificate, you get the full classification and can ask more precise questions.
Who is responsible for the details?
Under section 87 (1) GEG, sellers, landlords, lessors, lessors under leasing arrangements or brokers are responsible, insofar as they are responsible for the publication. For you as a prospective tenant, what counts is who publishes the listing and whether that party can supply the details.
What you can do now
- Check every listing against the mandatory details in the table before you decide on a viewing.
- Note the efficiency class, the final energy demand and the heating type, and roughly convert the quantity.
- If details are missing, ask the provider for the energy certificate before you sign any documents.
- Compare flats with similar size and similar use, so that the figures remain comparable.
Which questions you can ask at a viewing
- Is there an energy certificate, and is it a demand or a consumption certificate?
- Which energy sources supply the heating, and how is the hot water produced?
- How high were the heating and service charges in the last full billing year?
- Are there planned modernisation works that could affect the rent?
The answers complement the mandatory details and show whether the figures in the listing match reality. A question about the certificate is straightforward, and a question about consumption values belongs in every serious viewing. Evasive answers are a reason to ask more precisely.
This also helps to put the efficiency class into context. Anyone who notes the answers can compare flats later on objective grounds instead of relying on memory of the viewing. This matters especially when several offers are reviewed in a short time.
How to compare figures from different listings
Flats are comparable only if their size, use and building age are similar. An older building with a high final energy demand and a new building with a low value cannot simply be set side by side, because the buildings were built and used differently. Anyone who still wants to compare should always place the per square metre figure and the type of certificate next to each other.
Related reading
- Climate, Energy and Costs 2027: The overview for tenants and students
- Building Modernisation Act: What changes for tenants when heating
- Heizkostenabrechnung prüfen: Deadlines, allocation and typical errors
- Heizungstausch in der Mietwohnung: Wer entscheidet und wer zahlt
Last updated: November 2026. This guide is general information, not individual advice.
