Complete renovation of a 60s house - is KFW85 possible?

Interesting to hear. So really €330k just for the renovation without etc.? That's almost €2450 per square meter – you can build new to that standard.

Unfortunately, that's often the case. I don't know many people who have renovated, but those I know almost all say "I wouldn't do it again." Most report that the costs ended up so high in the end that they could have built new for that money. Others don't renovate completely to save a lot, but then often have the construction site feeling for a long time.

It always depends. In the end, we are at about half the price of new builds. A new build for 190sqm would easily have been 600k plus demolition of the old house. Renovation now <400k and there are still subsidies, so in the end we are at about 1700€/sqm.

The facade was already somewhat insulated, we didn’t touch that and we didn’t dig out the basement. Otherwise, everything is new including significant floor plan changes (about 15 new steel beams).

It always depends. In the end, we are at about half the price of new construction. New construction for 190 sqm would easily have been 600k + demolition of the old house. Renovation now under 400k and there are still subsidies, so in the end we are at about 1700€/sqm. The facade was already somewhat insulated, we didn’t touch that and didn’t excavate the basement. Otherwise, everything is new including significant floor plan changes (about 15 new steel beams).

Are the 1700 euros/sqm including own work or did you have only the specialist companies do the work?

Only professional companies. Own work = tearing off wallpaper and disposing of waste or knocking down a small wall (non-load-bearing). But very limited, as we have 2 small kids.

Roof: 50k
Photovoltaics: 20k
Windows + front door: 30k
Shell construction: 30k
Electricity: 25k
Drywall: 10k
Insulating basement ceiling: 5k
New water installation: 25k
Radiators: 17k
Heat pump: 30k
Bathrooms: 30k
Fireplace: 4k
Plasterer/painter/sanding and repairing floors/baseboards/exterior painting all one company: 50k
Architect: 35k
Kitchen: 20k

=~ 380k pretty much 2000€/sqm, a bit of small stuff will be added (container fees, portable toilet etc.)

Minus subsidies:
12,000€ roof + basement ceiling (individual building envelope measures, application '22)
30,000€ for heating + water installation, possibly more if we also get something for the bathrooms (application '23, 2 residential units – we missed it in '22...)
6,000€ for windows via tax declaration
2,000€ for photovoltaics (city subsidy)
4,000€ building envelope + windows + roof (city subsidy, based on sqm roof area, window area etc.)

=~326k = 1715€/sqm

But it must be said that we have a relatively small footprint (2 full stories + steep roof with 2nd attic floor with high room height) and thus, for example, our roof is relatively small – with a larger footprint, it can also be significantly more expensive...

Unfortunately, that's often the case. I don’t know many people who have renovated, but those I do know almost all say "I wouldn’t do it again." Most report that the costs ended up so high that they could have built new for that money.

This applies especially and all the more when a "surprise package" with moderate substance analysis and planning is tackled and worked on bit by bit as money and time are available. The most expensive are strategy changes due to information gained only during the process, imprecise quantity and volume determinations, as well as missing detailed planning. In all these cases, construction services from the most expensive category come into play: the so-called hourly rates.

Others don’t renovate completely to save quite a bit, but then often have a construction site feeling for a long time.

"Completely" in the sense of renovating to "current standards" can only be done to a limited extent. Usually, the limit for an economically proportionate lasting renovation lies somewhere between halving the age of the house and a condition of "today as it was 30 years ago." And not to forget: houses from the interwar period regularly have better-quality substance than those from the postwar period, although the latter are clearly younger when counted in years. But there are good and bad vintages, and the 1950s lasted until about 1963.

When I look at our energy consultations over the past years, a KfW70 (possibly with EE) is usually achievable. KfW55 often fails because of thermal bridges, especially when the floor slab is the system boundary. The basement ceiling is of course optimal here because you can then keep the thermal bridge surcharge below 0.05W/(m²K), often 0.03W/(m²K) is already required for a KfW55, which can fail quickly. (Reference always DIN 18599) Of course, with a heat pump it is good to approach KfW55, although the EE via photovoltaics plays almost no role here, unless a cooling capacity is covered with it, which becomes almost pointless with a KfW55. Then you can also stay with radiators if the effort for underfloor heating becomes too great.