Cost estimate for renovating a 1970s semi-detached house according to KfW or BAFA

Roof renovation is difficult to assess like this. Will the roof frame remain? Will the rafters be doubled or maybe roof insulation? But honestly, I don’t see more than 50k there. Photovoltaics depends. If you have 98m2 (south?) including roof windows, maybe about 7 kWp can be installed later. You might be able to get it ready-made on the market for 10-12k€.

I don’t believe in painting work in EL now. If you renew electrical and sanitary installations, you have to plaster completely except maybe ceilings, stairwell, and one or two rooms. That costs money (15-20k).
You also need new screed with underfloor heating.

Electrical work with 20k is also, I think, the lower limit.

Windows for 20k should work.

A schedule of one year only works if you coordinate well and the people come when you want.

If you redo the electrical and plumbing, you have to get everything plastered completely

Why? It depends on whether and how much chasing has to be done. Maybe a lot of the electrical work can go over the floor as part of the new floor construction.

You also need new screed

Fortunately, that is one of the cheapest items. Ordinary cement screed should cost around €2,500-3,000. With an accelerator to be able to proceed quickly, maybe €500 more.

I still don't see the roof as that expensive. For 165 sqm we paid about €350/sqm for everything, which would be about €35K for you. Plus possibly a regional surcharge, but certainly not almost double. Photovoltaics: Is the roof oriented East/West or North/South? With East/West both sides would make full sense, with North/South only one side --> has a strong impact on the costs.

From purchase to move-in ready in 1 year is unrealistic. Better plan for 1.5 to 2 years. The transfer of ownership alone can take 2 months and especially electricians and roofers are notoriously fully booked.

The roof is oriented East/West. So recommendation is to fully cover the roof?

I would suggest checking out the Photovoltaik-forum (google). In principle -- especially if a WP is planned at some point -- you can say: East/West is good for self-consumption (sunlight earlier in the morning, sunlight longer in the evening), South is better for maximum kWh yield (more peak power). Then it's a question of how you deal with the possible dormer etc.

Why? It depends on whether and how much needs to be channeled. Maybe a lot of electrical wiring can be run through the floor as part of the new floor construction.

Fortunately, this is one of the cheapest items. Normal cement screed should be around €2,500-3,000. With accelerator, so you can continue quickly, maybe €500 more.

Well, if I want more sockets, switches, and network, the things just come out in the wall later. Maybe also electric shutters right away… depending on what you actually do. You always see patched plaster.

Yes, screed without insulation work I think €3k is realistic.

Well, if I want more sockets, switching points, and network connections, the things just come out of the wall later. Maybe electrical shutters at the same time... Depending on what you do. You always see repaired plaster though.

No. You don't see that. That's a prejudice. Feel free to come by and/or I can take you along to our customers' construction sites.