Questions about the construction description

Hello everyone,
I am just starting to deal with the topic of buying a house. I have been offered a house and have already been able to clarify many things.
At the moment, I am a bit stuck evaluating the construction.

I would be happy if someone could tell me something about the attached building description.
Does the wall have to/can be insulated?

The house is from 1973 and quite a lot would need to be done (windows, insulation of the upper floor ceiling).

Consumption value 193 kWh with a 10..0 liter oil tank ; -

According to the building description, the house is constructed very simply, perhaps deliberately in the style of a smallholder’s plot, as can be read above in the building description. Was the house completely newly built in 1973 or extended in 1973, with the actual "Kern-Haus" possibly having been built 15 years earlier? The basic construction with 15cm KS exterior walls would also have been unusually economical for the time. Normally, at least 24cm KS or HBL exterior walls would have been used. If the upper floor/attic is to be developed, the statics of the ceiling above the ground floor should be checked.

However, the house was built before the first thermal insulation ordinance came into effect in 1977 and therefore without any legal requirements regarding the thermal insulation of building components. The final energy demand of such a house is probably around 250-300 kWh/m2*a. The specified 193 kWh probably comes from an energy certificate based on consumption and should be viewed with skepticism.

Such a house can be comprehensively renovated energetically. There are, among others, several funding programs from the KfW bank for this purpose. Before purchasing, the building fabric should be thoroughly inspected, for example for moisture exposure and other building damage and for the general condition of preservation. The ownership, building, and planning law situation should also be examined, because in such small settlement areas there are often special planning law requirements that may restrict remodeling, extensions, changes of use, etc.

If you are interested, I can gladly send you more detailed information on real estate purchase consulting. During an on-site appointment, the possibilities of energetic renovation can also be discussed.

Hello Wpic,
So the procedure was carried out according to din v 4108-6 and din v 4701-10.
Energetic quality of the building envelope 0.96 This value interests me the most.

I currently have a reserve of about €50,000 for renovation. The question is whether that is enough.

The two DIN standards probably refer to the energy performance certificate and are the basis of the Thermal Insulation Ordinance and the Heating Systems Ordinance. The value of 0.96 relates to the transmission heat loss of the building and is very high, but to be expected for a building of this construction age. For the energy refurbishment of a residential building built in 1973 in Nideggen, which I am currently planning, I have calculated a comparable value, with a final energy demand of 240 kWh/m2*a. For this reason, the value of 193 kWh/m2*a you specified is, in my opinion, set too low.

The costs of energy refurbishment can only be estimated after a building survey. They depend on the size, the basic structural construction, and the condition of the building. Such a refurbishment should, if possible, always consider the entire building envelope and the technical systems (heating) in order to avoid building physics disadvantages on components that remain uninsulated. Also, any construction damage/moisture damage must be located and repaired beforehand.

That also explains the 10,000-liter tank. So, I don't want a low-energy house but fear that at least 20,000 will be added to the 50,000, and then there are always enough other risks. Thanks for the contributions, they helped me a lot.

If you want to consult a property purchase advisory before buying in order to realistically estimate the condition and the renovation effort - also in regard to your budget - you are welcome to contact me. I provide advice for purchases throughout NRW.