An energy certificate (Energieausweis) rates how much energy a building needs or uses for heating and hot water, on a scale from A+ to H. When you buy a home in Germany, the seller or the estate agent has to show it to you at the viewing at the latest and hand it over once the purchase contract is signed. It is valid for ten years and describes the whole building, not your flat. It is a guide to likely heating costs and future work, not a promise of either. Some rules change on 1 January 2027; this guide gives both, with the date.
1. What an energy certificate is
The certificate exists only to inform: it describes the building's energy performance so that buildings can be roughly compared (§ 79(1) GModG). The law behind it is the Buildings Modernisation Act (Gebäudemodernisierungsgesetz, GModG), the new name of the Buildings Energy Act (GEG) since its 2026 reform (BGBl. 2026 I Nr. 226). Older listings and articles still say GEG; the rules on certificates are the same sections.
- One building, one certificate. It is issued for the whole building (§ 79(2) GModG). For a flat, you see the certificate of the block it is in; a top-floor flat under an old roof may do worse than the average, a middle flat better.
- Ten years. A certificate is valid for ten years. A major renovation that is recalculated for the whole building ends it sooner, because a new one is needed (§ 79(3) GModG). The expiry date is printed on it.
- Who issues it. Only qualified people may: architects and engineers with the right training, certain master craftspeople, chimney sweeps and technicians (§ 88 GModG). Each certificate carries a registration number.
- Digital from 2027. From 1 January 2027 a new certificate is issued in a machine-readable digital format, and on paper only if the owner asks (BGBl. 2026 I Nr. 226, Art. 2 no. 31). Certificates issued before stay valid for their ten years.
- Not every building has one. The certificate rules don't apply to small buildings of no more than 50 m² of usable floor area, and for a listed building (Baudenkmal) the duty to have and show one on a sale or letting doesn't apply (§ 79(4) GModG; § 3(1) no. 17 GModG).
2. Demand or consumption: the two kinds
A certificate is either a demand certificate (Energiebedarfsausweis) or a consumption certificate (Energieverbrauchsausweis); it may show both (§ 79(1) GModG). The listing has to say which one it is.
- Demand certificate. An expert calculates the energy the building needs from its walls, roof, windows and heating, under standard assumptions about weather and use (§ 81 GModG). It describes the building, whoever lives in it, which makes buildings easier to compare.
- Consumption certificate. It takes the real heating and hot-water bills of at least 36 months in a row, the latest of them ending no more than 18 months before, and adjusts them for the weather (§ 82(3), (4) GModG). It is cheaper to have made, but it also reflects how the last occupants heated: a single person away all week leaves a better number than a family at home all day. From 1 January 2027 new consumption certificates are allowed only for buildings used purely as homes, rest on two years of readings, and are adjusted for how the occupants used the building as well as for the weather (BGBl. 2026 I Nr. 226, Art. 2 no. 32, new § 82).
- Which one a seller needs. Usually the owner may choose. A residential building with fewer than five flats whose building application was made before 1 November 1977 needs a demand certificate, unless it met the 1977 insulation standard when built or has been brought up to it since (§ 80(3) GModG). That rule ends on 31 December 2026; from 2027 only buildings that aren't homes must have the calculated kind (BGBl. 2026 I Nr. 226, Art. 2 no. 32, new § 80(3)).
3. Reading the certificate
For a residential building, the class follows directly from the final energy figure (Endenergie), in kilowatt hours per square metre of the building's usable floor area per year (§ 86 GModG, Annex 10):
| Class | Final energy, kWh per m² a year |
|---|---|
| A+ | up to 30 |
| A | up to 50 |
| B | up to 75 |
| C | up to 100 |
| D | up to 130 |
| E | up to 160 |
| F | up to 200 |
| G | up to 250 |
| H | more than 250 |
Beyond the class, the certificate has to show (§ 85 GModG):
- Final and primary energy. Final energy is what the building takes in, the gas, oil, district heat or electricity you pay for; it sets the class. Primary energy adds what it took to produce and deliver that energy, so heating with wood pellets, for example, shows a low primary figure next to a middling final one.
- The year the building was built and the year of the heating. The heating's age hints at when it may need replacing. Ask what was renewed since: windows, roof, heating.
- The main energy sources for heating and hot water, and the greenhouse gas emissions in kilograms of CO₂ per square metre a year.
- Modernisation recommendations. The expert lists cost-effective improvements, or notes that none are possible (§ 84 GModG). They are short pointers, not a renovation plan or a quote.
Listings in commercial media have to give the key figures when a certificate exists: its kind, the final energy value, the main energy source, the year of construction and the class (§ 87(1) GModG). For a certificate issued from 1 January 2027 the listing shows the primary energy figure and the date of issue instead of the final energy figure; listings based on an older certificate keep today's figures. The A+ to H scale for homes stays (BGBl. 2026 I Nr. 226, Art. 2 nos. 34, 45 and 54).
4. What the seller has to show you, and when
The duties fall on the seller and on the estate agent alike (§ 80(3), (4) GModG):
- A certificate has to exist when a building, a flat or a leasehold is sold, unless the building has a valid one already.
- At the viewing at the latest the seller or agent shows it to you, as the original or a copy; hanging it up or laying it out visibly at the viewing is enough. Without a viewing, they show it without delay, and in any case as soon as you ask for it.
- After the contract they hand it, or a copy, to you without delay.
- A free advice talk for a house with no more than two flats, until the end of 2026: after receiving the certificate, the buyer has to have an informational conversation about it with someone entitled to issue certificates, where such a conversation is offered free of charge as a separate service (§ 80(4) GModG, last sentence). The duty is dropped from 1 January 2027 (BGBl. 2026 I Nr. 226, Art. 2 no. 32); the other duties above stay.
Not showing or not handing over the certificate, and leaving the figures out of a listing, are administrative offences with fines of up to €10,000 (§ 108 GModG). In practice, asking for it early is usually enough. If it is missing at a viewing, ask by email and keep the answer.
5. From the class to a heating bill
The certificate gives energy per square metre; your bill depends on the floor area, the price of your energy and how you heat. The arithmetic, with round numbers: a house with 150 kWh per m² a year (class E) and 120 m² of usable floor area uses about 18,000 kWh a year. At 12 cents per kWh that is about €2,160 a year; at class C (100 kWh) about €1,440. Prices differ by energy source and contract, and the floor area on a certificate is often larger than the living area, so treat this only as the method.
What a weaker class means for you, both ways:
- It can be the opportunity. KfW's Jung kauft Alt programme lends families towards buying a home in class F, G or H, on the condition that it is renovated afterwards; the KfW guide has the rules.
- It is a budget line. Higher heating bills and the work the recommendations point to belong in the budget from the start, next to the loan. Planned before you sign, a renovation can go into the financing alongside the purchase.
- For a flat, it is a shared decision. Insulating the facade or replacing the central heating is up to the owners' association, and its cost reaches you through the reserve or a special levy. The Hausgeld guide explains how, and what to read in the minutes before you buy.
6. Duties that come with a house
One retrofit duty can pass to you with a house. A top-floor ceiling (oberste Geschossdecke) that doesn't meet the minimum insulation standard has to be insulated, or the roof above it. For a house of one or two flats whose owner lived in one of them on 1 February 2002, that duty waits until the house changes hands: the new owner has two years from the first transfer after that date (§ 35(1), (3) GModG). Ask the seller whether the ceiling or roof has been insulated, and when. For a house of up to two flats where the owner lives in one, the duty doesn't apply if the cost wouldn't pay for itself through the energy saved within a reasonable time (§ 35(4) GModG).
Heating rules changed with the 2026 reform. The former duty to replace many gas and oil boilers after 30 years (old § 72) and the 65 % renewable-energy rule for new heating (old § 71) were repealed (GModG, table of contents). What applies now, if you replace the heating:
- You choose the system. A heat pump, district heating, a biomass or hybrid system, or gas or oil are all options (§ 42(2) GModG).
- A new gas or oil heating installed in an existing building after 29 July 2026 has to run on a rising share of biomethane, bio-oil or hydrogen: at least 10 % from 1 January 2029, 15 % from 2030, 30 % from 2035 and 60 % from 2040 (§ 43(1) GModG). Solar thermal panels or a heat-pump hybrid can count towards it. Those fuels are usually dearer, which belongs in the comparison.
7. Letting the home later
The same certificate serves when you let: a landlord, or the letting agent, shows it to prospective tenants at the viewing and hands it to the new tenant (§ 80(5) GModG), and the listing carries its figures. From 1 January 2027 the same applies when a lease is extended (BGBl. 2026 I Nr. 226, Art. 2 no. 32). Keep the one you receive with the purchase and note its expiry date. The buy-to-let guide covers the rest of letting.
8. When a financing expert can help
A weak class doesn't rule a home out; it changes the numbers. A financing expert builds the heating costs and any renovation into the budget alongside the loan, checks whether a KfW loan can be part of it, compares lenders' offers for you, and tells you what each one needs to see about the building. Have the listing, the energy certificate, any renovation quotes and your own income documents ready. You can ask for a financing expert who works in English.
Primary sources checked on 2 November 2026: the statutes and official pages linked above.