What will your renovation cost? Measure by measure.
Façade insulation at 130 – €250 per m², a heat pump at 12,000 – €25,000, full renovation at 600 – €1,800 per m² of floor area: this calculator adds up sourced cost ranges for your chosen measures — installation included, before subsidies.
Updated: Benchmarks 2025, retrieved 25 Sep 2026
130 – €250 per m² façade
55 – €150 per m² roof
20 – €80 per m²
400 – €1,200 per windows
12,000 – €25,000 per system (total)
600 – €1,800 per m² floor area
Reference ranges per measure, including installation, before subsidies. Building condition, region and materials decide where you land within the range.
For renovations BOB recommends a 15–20% reserve — old buildings surprise more often than new ones.
How this calculator works
- 01
Choose measures, adjust quantities
You pick measures and set your quantities: square metres of façade, roof or basement ceiling, number of windows, floor area. For the heat pump BOB uses total cost per system.
- 02
Sourced range per measure
Every measure carries its own cost range with source and date — mostly from co2online and trade portals. BOB invents no numbers: anything without a solid source does not appear in the calculator.
- 03
The sum stays a range
The sums of lower and upper bounds form your total range. The building’s condition decides where you land — a 1960s house with a damp basement is different from a 1990s one.
- 04
Reserve for surprises
For renovations BOB recommends a 15–20% reserve — more than for new builds, because any opened wall can hold a surprise.
Benchmarks include installation, before subsidies; excluding special scaffolding, hazardous material removal and heritage constraints. Not energy consulting. Figures refer to Germany.
Frequently asked questions
As a benchmark 600 – €1,800 per m² of floor area — depending on condition, region and standard. For 120 m², roughly 72,000 – €216,000. From about half the cost of a new build, honestly compare: renovate or rebuild?
For an air-to-water heat pump in an existing building, the total range is 12,000 – €25,000 including installation, before subsidies. German BEG subsidies reduce the net cost considerably — the calculator deliberately shows pre-subsidy costs because programmes change.
Deliberately not. German subsidy programmes (BEG, KfW, states) change constantly; baked-in grants would quickly be wrong. Calculate gross costs and subtract the subsidy actually granted — in BOB you track it as its own funding source.
They are sourced benchmarks, not quotes. Within one measure, scaffolding, disposal, hazardous materials or heritage rules can move the price. The range tells you whether you are thinking about €30,000 or €90,000 — real prices come from quotes, which you compare line by line in BOB.
Rule of thumb: first the envelope (roof, windows, façade), then the systems (heating, ventilation), then surfaces. Sizing the heating before insulating usually means buying too big. An energy consultant’s renovation roadmap adds structure — and, in Germany, extra subsidy points.