ᐅ U-values for heat loss according to regulations, comparison for KfW85 loan requirements

I’m just going to join in on this thread. I’m going to renovate a house built in 1973. It was constructed with concrete blocks. I basically just want to replace the windows and insulate the roof structure. Or would external insulation make sense for concrete blocks? (The heating is oil and a wood-burning stove)

Hello, I have a question: Didn’t your energy consultant explain the report? Regards

Hi, he actually took quite some time. To be honest, at some point I stopped following (technical terms, calculations, etc.) – but he didn’t say: do this and that (okay, after all, he doesn’t profit from the renovation) but only: you could do this and that. Since we also want to renovate the interior (bathroom/toilet, doors, etc.), it would be important to know whether we should invest the money better in external insulation with a ventilation system or rather in the interior. This is also relevant regarding the necessary KfW loan. With the insulation, we could claim a "comprehensive measure" from KfW (larger loan). Good luck, Alex

Hi,
what material did the consultant assume for the exterior wall, and what U-value and lambda value were used for it?

Sorry, if you click on replies too early, this is what happens:
Once again:
What thermal conductivity (lambda) value did he assume for the exterior wall material to achieve a U-value of 0.60?

frenchfriesguy schrieb:
.....But is that really necessary for 36cm (14 inch) bricks? Do I need such a low U-value? (possibly a requirement for KfW loans?)....In addition, of course, a mechanical ventilation system would also be installed.

What is necessary is always determined by the client! Simply "insulating" is often only half the story if the heating system is not also properly adjusted! ;-) Very often, the optimistic calculations from energy consultants fall apart if the entire building and its mechanical systems are not considered together!

Best regards