ᐅ Insulating a New Build with 36.5 cm Aerated Concrete Blocks?

Alex85 schrieb:
Since I’m from Schleswig-Holstein myself and maintain a circle of acquaintances there, I can only say: No.
What do you think typically lies behind the common red facing brick?

Well, almost always Ytong, Porit, Hansapor, Hebel... at least since around 2000.

Grym schrieb:
So it seems that Commerzbank can actually offer the online terms in practice. Anything else would be fraud, right?

Not exactly. These are usually not the conditions according to the Price Indication Regulation. Moreover, Commerzbank generally acts more as an intermediary.

Alex85 schrieb:
Yes and no. These are usually not the terms according to price indication regulations. Especially since Commerzbank tends to act as an intermediary.

So once again, Commerzbank has an online calculator, and if you consider that it offers 2 months without commitment fees, while the branch offers 12 months interest-free availability with an interest surcharge of 0.06 to 0.08 percentage points, then the online conditions are also the conditions that were offered to us. If we had said on that day that we would go ahead, those would have been our terms.

The contract is then concluded between us and Commerzbank. Whether they resell the loan, no idea. Comdirect acts as the broker, is that who you mean?

2.08% for 20 years
1.16% for 10 years
Each with 2% repayment, 2 months no availability interest, and 80% loan-to-value

KFW 55 at 2.25% for 20 years with simultaneously higher repayment obligation as well as KFW equity at 1.50% for 10 years also with higher repayment obligation do not make sense currently.

But that is just a side issue.

Originally, the point is that external thermal insulation composite systems (ETICS) hardly save any energy costs compared to a solid (monolithic) wall. In my example above, about 500 EUR over 50 years.

Compared to ventilation losses, windows, and domestic hot water, the other factors are minor.

Therefore, I do not decide between sand-lime brick plus ETICS or solid construction based on manufacturing costs or energy savings, but rather on what I feel comfortable with over 50 years or more and where I know (!) that no major renovation or disposal costs will await me.

Grym schrieb:
Here in our area, many ETICS facades are already undergoing renovation. Of course, you could say that ALL of them were improperly installed, which may partly be true, and it is noticeable that this often affects houses without roof eaves.

When adding an extra layer of insulation boards, not aligning the roof eaves with the shifted outer wall surface is probably a "classic" mistake. At least when the roofing is not being replaced.

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Grym schrieb:
I already have a preliminary calculation, and it shows 42.7% heat loss through ventilation, 26.9% through glass, and 10.8% through the exterior wall. And this is based on heating energy.

Statements like this are exactly why no one took you seriously in the green forum. I don’t know if you just made up the numbers or invented them for fun, but you just need to google for 5 seconds to see that your figures are complete nonsense.

42.7% through ventilation... excuse me? No windows installed? (That would also explain the way too high heat loss through the windows).

With numbers like these, you might as well skip any calculations. Garbage in → garbage out. Apart from that, economic efficiency is not my point in this discussion. That a lot doesn’t pay off... I fully agree with you. By the way, aerated concrete was the cheapest option for us, followed by sand-lime brick plus external thermal insulation composite system (ETICS), then our current facing brick.

What I was getting at:
The blanket dismissal of ETICS with arguments you read somewhere, presenting them as if they are established expert opinions without ever citing any source.

Example:
You claim that ETICS is more likely to require earlier renovation than monolithic construction... Strange, the Fraunhofer study says that proportionally more damage was found on facades of monolithic systems. For example, they also had significantly more problems with thermal bridges. ETICS itself lasts forever...

The ominous woodpecker... sure, that definitely counts as facade damage, but it hardly ever happens. Wow, there are very few documented cases on the internet... how can you build an argument on that?

Algae: Quite a bit has already been said. Not a problem unique to ETICS facades; facing brick and monolithic buildings have it just as severely. It might occur slightly more often on ETICS, but the surrounding environmental influences have a much greater impact (trees, biotopes, ...).

I understand that emotionally many dislike plastics, but that’s purely an emotional issue and we’ve been over this several times here. You would then have to give up yogurt containers, toothbrushes, your sofa in the living room, and thousands of other things. You even have direct skin contact with some of them or ingest them through food. ETICS is simply inside the wall, with no contact to the outside environment…

19 windows will be installed, and the numbers were determined by a specialist using professional software. As far as I can verify the inputs, no errors were made.

I have no issues with plastic, but if it is not necessary, then it is better to avoid it.

The Fraunhofer study rates the External Thermal Insulation Composite System (ETICS) so positively because it was regularly maintained and renovated. This is exactly what I mean: follow-up costs!!

A lifespan of 22 years until the first renovation is given, based on the 2–6 cm (1–2.5 inch) thin ETICS panels from back then.

Other types of damage occur exclusively or more frequently with ETICS, such as woodpecker damage, algae, cracks, blisters, and stains.

For renovation, there is no alternative, but for new builds, it is not worth taking any risk—for even 10 euros in heating costs per year—no matter how small that risk might be.