First house purchase, year of construction 1962, how much will a renovation cost?

Hello and good morning,

my wife and I, both in our late 30s with an almost one-year-old son, finally want to "put our money where our mouth is" and buy a home. Since this will probably be the most expensive purchase we will make in our lives, I admittedly get a bit overwhelmed regarding the renovation and operating costs; we definitely don’t want to overstretch ourselves! I hope you can assess whether our budget is sufficient and if the house is worth buying.

The details are:
- Year of construction 1962, solid construction. 24cm brick, 2cm air gap, then 4cm clinker bricks.
- 160m² living area on 1.5 floors
- 100m² usable area in the full basement
- 1200m² plot
- 6.5 rooms
- Cold roof with rendered Frankfurter tiles

What has been done (the current owner bought it 3.5 years ago, it took another 1.5 years until the tenants moved out and he started the renovation. However, he separated from his wife a few months ago and wants to get rid of it; the separation has apparently affected him very much):
- Electrical system on the upper floor including fuse box
- All windows on the upper floor
- Gas condensing boiler for heating and hot water

We had the house inspected by an expert. There seem to be no major problems with the structure, the roof is fine, the basement is not bone dry but uncritical. However, he pointed out that the house should be brought to a better energy standard.

What we plan:

- Renew insulation between the upper floor ceiling and the attic, mineral wool without a vapor barrier is planned, and where necessary (for example, to access the chimney) chipboard panels so that moisture is not trapped underneath. We want to do this ourselves.
- New windows on the ground floor (plastic with double glazing is planned)
- New front door
- New terrace door
- Both bathrooms to be renovated
- Kitchen needs to be installed
- Electrical wiring on the ground floor is still two-wire, needs to be redone too.
- Close all radiator niches, move radiators forward
- Insulate dormer sides and top
- Install dormer windows properly (the foam filler was exposed unprotected for months and has weathered)
- Remove glass blocks in the stairwell and replace with windows
- New floors
- Paint the walls
- New interior doors with frames

Where we are unsure if it’s worth it or if we have to do it:

- The heating pipes in the walls seem to be steel and very thick (I saw supply lines with 1/2 inch and return lines with 3/4 inch), do they absolutely have to be replaced or are there other options?

What matters to me most:
- Are these measures suitable to make heating costs economical? The house has no energy certificate (which probably would look bad). I have no idea how much heating this house would cost. Is all this effort worthwhile, or will we still be burning money?

Thanks a lot for reading this far, I know these are a lot of questions, but I’m really a bit nervous, after all I’m putting all my savings into this (40,000 to the bank and 40,000 for the most important renovations), which makes me pretty anxious.

We want to do everything with family, except wiring the fuse box and the questionable heating connections, we have professionals in the family (door and window builders, drywall installers, masons). I probably forgot some information, I will provide it as best as I can.

Thanks again for your help!

Best regards Patrick

...here are more photos, all are named with the room names from the floor plan.

...and more.

...more photos:

How is the insulation against the ground or the basement ceiling against the ground floor? And nothing is supposed to be done on the facade? The larger the insulated area, the better. An energy consultant (dena!) could take a look on site and give helpful tips on what makes sense or offers the most value for the money. They can also identify thermal bridges, which from here can only be speculated about remotely.