Condition
Inspection of the building with a focus on the roof, external walls, windows, basement ceiling and heating. Review of the energy performance certificate, plans and consumption bills, as far as the seller provides them.
Energy advice before buying a house
With an older house, its energy condition partly determines the costs you will still face after the purchase. Many loans for the purchase also require the building to improve by one or more efficiency classes within a set period. I assess the renovation needs before the notary appointment and support the renovation after the purchase through to the proof for the bank.
Why before the purchase
The sales brochure (Exposé) usually only states the efficiency class from the energy performance certificate (Energieausweis). It does not tell you what renovating this house will actually cost, which building components are due first and which funding may be available for them. Yet these are exactly the figures you need for negotiating the price, and the bank needs them for the financing.
There are also deadlines: if you use a loan with a renovation requirement, you must prove the improvement within a fixed period. And after a change of ownership, one- and two-family houses are subject to specific retrofit obligations under the Building Modernisation Act (GModG, formerly GEG), which replaced the Buildings Energy Act (Gebäudeenergiegesetz) in July 2026. If you know this before signing, you can plan budget and timescale realistically.
What I check before the purchase
I put the scope together according to your plans and your loan. One example is a demand-based certificate (Bedarfsausweis) for which I survey the building envelope on site instead of using standard values by building age, supplemented by a look at renovation options. For the site visit I need the seller's consent and access to all floors, including the basement and the loft.
Costs and funding
An assessment of which measures will be due in the coming years, with a rough cost range and the funding programmes that may apply.
Efficiency class
An assessment of which measures will bring the house to the efficiency class required by your loan, and which route is the most economical.
Consumption-based or demand-based certificate: what they tell you
The sales brochure states an efficiency class, but it can be based on two very different documents. For the purchase decision it matters which one it is and what it reveals about the house.
Consumption-based certificate (Verbrauchsausweis)
It is based on the actual heating energy consumption of the previous occupants, adjusted for weather. It therefore says a lot about the people who lived there: how warm they kept the house, whether all rooms were heated, how many people lived in it and whether it stood empty at times. For you as a buyer it is of limited value, because you will live there differently.
There is also the so-called prebound effect: in poorly insulated houses, occupants usually heat more sparingly than the standard calculation assumes. The measured consumption is then considerably lower than the calculated demand. After renovation this is often reversed (rebound effect), because heating to a higher temperature becomes affordable.
Demand-based certificate (Bedarfsausweis)
It calculates the energy demand from the building itself, that is from its components, heating and hot water, according to DIN V 18599 with uniform assumptions for room temperature, ventilation and climate. This makes buildings comparable regardless of their occupants. That is its purpose.
It is not a forecast of your future heating costs. For poor buildings, the standard calculation considerably overestimates the losses. Based on several studies, the German Environment Agency (Umweltbundesamt) puts the deviation at about 40 per cent for values around 300 kWh/(m²a) and at about 17 per cent for 150 kWh/(m²a). The quality of a demand-based certificate also depends on whether the building envelope was surveyed on site or only estimated using standard values by building age.
For the assessment before the purchase this means: a demand-based certificate with a surveyed building envelope shows where the house stands in energy terms and which components have the greatest losses. If consumption figures from the previous owners are available, I put the two side by side. This gives a more realistic estimate of heating costs and of the savings a renovation can actually achieve than either document allows on its own.
Note also: depending on the type of certificate, the same house can end up in a different efficiency class. This can decide whether a loan with a renovation requirement is an option at all.
Source for the deviations: Umweltbundesamt (German Environment Agency), ad hoc paper „Realitätsnahe Berechnung des Energiebedarfs“ (realistic calculation of energy demand), July 2022.
Loans with a renovation requirement
The terms differ between lenders and change frequently. What they all have in common: the condition before and after renovation is documented by an energy performance certificate or a confirmation from an energy consultant, and there is a deadline for the improvement.
KfW 308 „Jung kauft Alt“
Low-interest loan from KfW (the German federal development bank) for families with at least one minor child and a limited household income who are buying a home for the first time. At the time of application, the energy performance certificate must place the house in class F, G or H. Within 54 months of the loan approval, it must be renovated to at least Efficiency House 85 EE (Effizienzhaus 85 EE), or alternatively with four specified individual measures: replacing the heating system with one using at least 65 per cent renewable energy, new windows, façade insulation, and insulation of the roof or the top-floor ceiling. Depending on the number of children, the loan amounts to up to €180,000. KfW expressly recommends advice from an Energy Efficiency Expert (listed by dena, the German Energy Agency) before the purchase (KfW 308 information sheet, in German, status 08/2026).
Mortgages from banks
Several banks and direct banks grant an interest rate discount if the house's efficiency class improves through renovation within an agreed period. What counts are the conditions in the individual loan agreement: by how many classes, by when and with which proof.
Bring the loan conditions to our meeting. I will then check which measures achieve the required improvement and which funding can be used in addition.
How it works
- 1
Enquiry
Send me the sales brochure, the energy performance certificate and, if available, the conditions of your loan. I will get back to you with an estimate of the effort involved.
- 2
Site visit before the notary appointment
With the seller's consent, I inspect the house and review the documents available.
- 3
Assessment
You receive the measures that are due, with cost range, funding and the route to the required efficiency class, as a basis for price negotiation and the financing meeting.
- 4
After the purchase contract
Once the notarised purchase contract is signed, you can apply for funded energy advice. You do not have to wait for the entry in the land register (Grundbuch).
- 5
Renovation roadmap and applications
The individual renovation roadmap (iSFP) sets the sequence of measures and increases the funding for the building envelope. Then come the funding applications, and only after that are contracts awarded.
- 6
Implementation and proof
I support the works and prepare the proof for the funding body and the lender, including the new energy performance certificate if required.
Obligations after a change of ownership
If you buy a one- or two-family house, the Building Modernisation Act places retrofit obligations on you that the previous owner, as an owner-occupier, did not have. Within two years of the transfer of ownership, the top-floor ceiling must as a rule be insulated if it does not meet the minimum thermal insulation standard (Mindestwärmeschutz), and uninsulated heating and hot water pipes in unheated rooms must be insulated.
These obligations can be combined well with a funded renovation if the sequence is right. That is why they belong in the assessment before the purchase.
Frequently asked questions
Can the iSFP be prepared before the notary appointment?
The site visit and an assessment, yes, provided the seller grants access. As the buyer, you can only apply for the grant for the renovation roadmap once the notarised purchase contract has been signed. Before that, only the seller could submit the application. The sensible order is therefore: the assessment before the purchase, the funded roadmap after the purchase contract.
Do you also prepare the financing plan for the bank?
No, the bank prepares the financing plan. From me you receive the basis for it: the measures that are due, a cost range, the expected funding and the route to the required efficiency class.
We have inherited the house. Does the same apply?
Yes. In the case of an inheritance, the conveyance notice (Auflassungsvermerk) is sufficient for the application for funded energy advice; you do not have to wait for the entry in the land register.
Which documents should I request from the seller?
Energy performance certificate, floor plans and sections, building specification, documents on modernisation work already carried out, details of the heating system with year of manufacture, and the consumption bills for the last three years. Whatever is missing, I record on site. A detailed list is given in the preparation checklist (in German).
Is the energy performance certificate from the sales brochure sufficient as proof for the bank?
That depends on the loan agreement. A consumption-based certificate mainly reflects the heating habits of the previous owners and is poorly suited to proving an improvement after renovation. For a before-and-after comparison, a demand-based certificate is the better basis, ideally with the building envelope surveyed on site.
Request an assessment before the purchase
Send me the sales brochure, the energy performance certificate and the date of your planned notary appointment. You will receive a reply within two working days.