Start with condition and a defined target
Collect the building record, dimensions, construction layers, service condition and energy bills. Bills help describe actual use, but weather, occupants and hot water affect them; consumption alone does not establish a replacement heater’s design load. Discuss comfort, summer heat, moisture, noise and future use as well as energy cost.
Resolve active leaks and unsafe systems before enclosing them behind new finishes or insulation. Ask the adviser to distinguish a mandatory measure, a repair and a voluntary improvement. The current GModG is the post-July 2026 federal law; older GEG section numbers and advice need checking. The applicable procedure still depends on the property and planned intervention.
Use a coordinated roadmap, then develop the design
An individual renovation roadmap (iSFP) sets out the existing energy condition and coordinated steps suited to the owner. It can support staged decisions without obliging you to carry out every proposal. Keep its implementation guidance, assumptions and date. A roadmap estimate is not an accepted construction quotation or a funding commitment.
Ask which specialist design, quantities and execution details are still required. Define the eventual envelope target before sizing future heating. Also plan hot-water demand, emitter performance and distribution. A heater sized for the current uninsulated house may be a poor match after major envelope improvements; the actual solution needs calculation, not a simple area multiplier.
Resolve the interfaces before deciding the order
| Work | Interface to resolve | Procurement decision |
|---|---|---|
| Roof or attic | Leak repair, ventilation routes and future insulation | Coordinate roof condition before final coverings |
| Façade and windows | Window position, reveals, sills, shading and scaffold | Detail the connection even if contracts are staged |
| Airtightness and ventilation | Moisture protection and air supply/exhaust paths | Choose an assessed concept, not just a fan |
| Heating and emitters | Current/future heat demand, controls and electrical supply | Size for the agreed target and feasible transition |
| Interior finishes | Concealed routes and drying | Close surfaces after the relevant checks |
Window guidance emphasises the connection with the insulation layer; ventilation guidance explains moisture protection after airtightness changes. These are reasons for coordinated design, not a universal instruction that every house must receive the same ventilation equipment.
Compare the complete investment and its timing
| Item | Amount |
|---|---|
| Defined construction: EUR 79,000 net plus 19% | 94 010 |
| Initial energy assessment/roadmap allowance | 1 785 |
| Subsequent design and construction checks | 5 950 |
| Shared scaffold and external logistics | 4 760 |
| Identified unresolved detail | 3 570 |
| Temporary living | 3 000 |
| Chosen reserve: 10% of gross construction | 9 401 |
| Full funding before any grant | 122 476 |
The scaffold is counted once here because the fictional programme has one coordinated period. If separate phases genuinely require another EUR 1,190 gross mobilisation, funding rises to EUR 123,666 unless another line is reduced. Do not present staged work as automatically cheaper simply because each individual payment is smaller.
Keep legal requirements, funding and economics separate
Current GModG section 36 addresses relevant changes to existing external components and refers to Annex7. Have the designer establish the actual requirement and applicability. A legally acceptable component does not necessarily meet a grant’s technical criteria. Equally, a product advertised as grant-eligible does not establish that the owner’s application qualifies.
Check the current BAFA envelope conditions before relying on an iSFP bonus; it is not automatically five extra points on every small job. Compare complete investment, maintenance, energy assumptions and finance costs over an appropriate period with the adviser. Do not add advertised saving percentages from separate products or promise that a modelled saving will equal the household’s future bills.
Allow a sensible emergency route
A failed heater or active roof leak may require immediate stabilisation. Ask the relevant professionals how a temporary solution and a future target can coexist. Avoid waiting through unsafe conditions merely to follow an “envelope first” slogan. Before committing to a funded measure, clarify the application and contract rules; emergency need does not automatically waive them.
- Record the existing condition and priorities.
- Choose a target and specialist responsibilities.
- Resolve envelope, window, ventilation and heating connections.
- Define complete packages and shared costs.
- Check programme-specific funding before commitments.
- Monitor scope, cash and actual outcomes.
Use Reno Pro for stages and payments, while retaining the iSFP, calculations and agreed specifications as supporting documents. A controlled sequence protects the future work from being blocked or paid for twice by today’s decision.
Sources, date and scope
- Verbraucherzentrale — Individueller Sanierungsfahrplan
- Bundesministerium der Justiz / Bundesamt für Justiz — Gebäudemodernisierungsgesetz — geltende Fassung
- Bundesministerium der Justiz / Bundesamt für Justiz — GModG § 36 — Änderung von Außenbauteilen
- Verbraucherzentrale — Fenster sanieren oder austauschen
- Verbraucherzentrale — Planung einer Lüftungsanlage
- BAFA — Einzelmaßnahmen an der Gebäudehülle
Checked on 19 October 2026. Local examples concern Berlin unless stated otherwise. Check state law, heritage protection, community rules and actual work for the specific project. Teaching figures are invented euro amounts, not market prices or offers. The article projects are independent. Tax and funding calculations apply only under the stated assumptions; competent professionals resolve project-specific technical and legal questions.