Buy an uninsulated house? Does it make sense?

Uninsulated but clad with facing bricks? Then beads in the cavity. It is cheap and effective.

Unfortunately, I have heard both good and bad things about this. Does it really make sense? I ask because we have such a cavity.

- When installing new windows, also keep in mind that they are very airtight. Consider ventilation or ventilation behavior!
- I would take a look at the electrics in such existing houses.
- Water pipes are often at the end of their lifespan after such a time.
- When the walls are open, also think about network, Sat, empty conduits.

Only windows/glass as a single measure can backfire if the wall is then colder than the window. Condensation is then not found on the window but on the wall and can cause corresponding damage. KFW subsidies for [energ. Sanierung] are not bad, I would take a look at them. Underfloor heating is pointless if the floor is not insulated.

About the little beads. We had to renovate a 1979 brick house for work. The heating engineer suggested triple-glazed windows plus these little beads. The result was surprisingly good. It cost around 15 and we saved and continue to save 3 thousand liters of oil annually in this rather large building.

The roof must be insulated under certain circumstances, which can be found in the Energy Saving Ordinance. It’s worth keeping in mind and might even be cost-effective. Insulating a clinker-brick house afterwards is, however, as already mentioned, not very sensible. Windows can be worthwhile, depending on their age. If an old woman alone consumed 220 kWh/m2, it could be 400 or 100 for you — you can’t know and should consider that. At 400, heating costs would amount to about €3500, compared to €500-1000 for a new building.

Replacing only windows/glass as a single measure can backfire if the wall then becomes colder than the window. Condensation will then not be found on the window, but on the wall and can cause damage accordingly.
KFW funding for energy renovation is not bad, I would consider that.
Underfloor heating is pointless if the floor is not insulated

Adjusted ventilation behavior has already been mentioned.

According to the initial post, the floor slab has been insulated.
If not, then insulate the basement ceiling.

If neither is present, then you are right. At least on the ground floor. The upper floor is unproblematic.