ᐅ Is it feasible to achieve a KfW 70 energy efficiency standard using exterior masonry with 17.5 cm autoclaved aerated concrete (AAC) blocks, 16 cm mineral wool insulation, and a brick veneer?

Hello everyone,

I couldn’t find any useful information online, so I have a question.
Is it possible to meet the KfW standard with a new build wall construction consisting of 17.5 cm (7 inches) sand-lime brick / 16 cm (6 inches) glass wool / 4 cm (1.5 inches) air gap and facing brick? I know that for KfW 70 not only the wall structure matters but also the energy source, windows, etc. However, in principle, would this be feasible? I am looking for an alternative to Poroton, and sand-lime brick seems like a good option, especially considering sound insulation and fastening possibilities.

Thanks for your answers.

Best regards,
Stefan

It’s hard to understand, isn’t it? First, you ask in another forum, then despite well-founded answers, you keep asking the same question, and now here again?

How many times do you want to receive confirmation—if any is possible given the limited information provided.

No, you don’t have to, but that doesn’t mean that all users of Bau*****s are active in the house building forum. And, as is well known, the answers often vary widely.

These are physical laws that have nothing to do with an opinion.

If you had asked this at the same time, but after receiving numerous answers, you ask the identical question again?

I did not rephrase the question but copied it, though that does not really matter. What bothers me is that some people react so defensively right away! It is certainly something physical, but I am still concerned about the statement of a bricklayer who is now a structural engineer, saying that this option is not advisable. That’s why I started a second thread. Maybe an expert in this field will share their opinion.

These are new details that were not mentioned in the original post...

Why do both of them not recommend it? It has nothing to do with KfW 70, since that is generally possible...

By the way, aerated concrete blocks are easier (simpler to handle) to work with for a mason.