ᐅ Poroton 36.5 or 42.5 with perlite or mineral wool insulation
Created on: 17 Feb 2021 14:00
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Freiburger2020
Hello everyone,
we are uncertain whether to go with a monolithic KfW40 or just KfW55 standard.
That means choosing between the Poroton T7 36.5cm (14.4 inches) or the 42.5cm (16.7 inches) insulated brick.
We are also undecided between using perlite or mineral wool insulation. I hope to get some input based on experience. The building contractor is not giving clear advice, with different opinions on which is better or worse.
Since we are building two residential units, we will receive double KfW subsidies, so the repayment grant is a strong argument in favor of KfW40 and the 42.5cm (16.7 inches) brick.
On the other hand, there is the actual loss of space with the 42.5cm (16.7 inches) brick compared to the 36.5cm (14.4 inches) one, and the fear that heating costs with the 36.5cm (14.4 inches) brick might become overwhelming after a few years.
We definitely want a solar system, which again supports going for the KfW40+ standard and the 42.5cm (16.7 inches) brick.
We look forward to your opinions.
we are uncertain whether to go with a monolithic KfW40 or just KfW55 standard.
That means choosing between the Poroton T7 36.5cm (14.4 inches) or the 42.5cm (16.7 inches) insulated brick.
We are also undecided between using perlite or mineral wool insulation. I hope to get some input based on experience. The building contractor is not giving clear advice, with different opinions on which is better or worse.
Since we are building two residential units, we will receive double KfW subsidies, so the repayment grant is a strong argument in favor of KfW40 and the 42.5cm (16.7 inches) brick.
On the other hand, there is the actual loss of space with the 42.5cm (16.7 inches) brick compared to the 36.5cm (14.4 inches) one, and the fear that heating costs with the 36.5cm (14.4 inches) brick might become overwhelming after a few years.
We definitely want a solar system, which again supports going for the KfW40+ standard and the 42.5cm (16.7 inches) brick.
We look forward to your opinions.
Nordlys schrieb:
We have—please excuse my little slip—a completely different setup: an exhaust fan and a window frame ventilator. So, a centralized solution for modest budgets, which works surprisingly well. Honestly? I think that’s a much better solution than decentralized units. And above all, the price-performance ratio is absolutely unbeatable.
In the bungalow of around 110 sqm (1184 sq ft), this really works. The motor is located in the bathroom, so its background noise is not disturbing. The fans are installed in all the windows; since it’s a FHZ system, the doors are usually open anyway, and air can also pass underneath the doors, as they are never sealed tightly at the bottom.
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Freiburger202017 Feb 2021 17:50Back to the question: Brick infill – perlite vs. mineral wool. I once inquired about mineral wool. What is the difference in sound insulation? The thermal insulation is the same, but what about the difference regarding moisture/water damage?
Perlite cannot get wet because it is hydrophobic. The wool absorbs moisture. This is an advantage of perlite. Otherwise, there are no differences. Oh, and perlite crumbles when drilling and cutting, so the wool is probably better in that regard. Wool is also about 30% cheaper.
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nordanney17 Feb 2021 20:17Bookstar schrieb:
Yes, I’m getting a bit emotional here because there are homeowners reading this, and they should be protected from making such mistakes.The central system is the real problem. Complex planning. Very expensive. The ventilation openings cause endless issues. The pipes quickly become breeding grounds for germs and bacteria. And then there are the costly filters. Loud airflow noise at the outlets. Sound transmission, so you can hear conversations from the ground floor in the attic. Visually terrible, especially what ends up mounted on the ceiling.This simply needs to be said to prevent new homeowners from falling for this nonsense. It only causes problems. Yet it’s highly praised so the house doesn’t start molding underneath, since everything is built airtight.
I’m well familiar with both systems. Both work quite well in comparison. In new construction, I would install a central system if the budget allows, but opt for a decentralized setup on a limited budget and also for renovations.
Okay, enough off topic. Back to the main subject.
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