ᐅ Is insulating the exterior wall worthwhile or not?

Hello, I need your help. We have a single-family house built in 1976. The exterior plaster looks like eggshell plaster, as my wife calls it. So, it’s not really attractive. This led us to improve the outside appearance by adding a wooden facade with narrow horizontal slats. Insulation was not originally planned. After a conversation with our window installer (we also got new windows), he suggested installing mineral wool insulation in the substructure. The substructure is 30mm (1.2 inches) thick. He said it wouldn’t be much effort and would bring some benefits. I have read a lot but still don’t feel much wiser. Does it make sense to install mineral wool directly in the substructure? It can only be up to 40mm (1.6 inches) thick. Is it useful or better to leave it out as unnecessary?

Have you ever heard of energy saving? Everyone is talking about it right now—you just need to read the newspaper or watch TV. If you’re going to work on your facade anyway, do it properly or don’t do it at all. Apply adequate insulation and do it correctly from a technical standpoint. Your current insulation is insufficient and would also be incorrect from a professional perspective.

I just want to know if it’s worthwhile or not! But according to your answer, it’s not. So, I can save the money for the insulation. Thank you very much for your help.

Yep, 30mm (1.2 inches) doesn’t make much difference. However, doing nothing is even more unreasonable and will be more expensive in the long run.

I wasn’t concerned with how to save energy, but rather whether my contractor’s statement was correct. That’s all I wanted to know. And yes, from time to time I did read the newspaper or watch TV...

Since you are renovating your facade, in my opinion there is even an obligation under the building energy act to install facade insulation.