New construction Poroton T7 MW 36.5 without controlled residential ventilation

What do you mean by decentralized solution?

What do you mean by decentralized solution?

A decentralized ventilation system. So no ducts running through the house, but a duct ventilation in each room.

If so, a central system will be installed in our house.

I received a revised offer today for a 2-story house (town villa) in which about €3,600 extra is charged for the T7 MW 36.5 compared to the T8, I find this a bit steep, don’t you? Is the extra cost worth it?

Yes, definitely. Purely based on the list price, the difference is about 250 euros per 1000 bricks. So you could calculate how much that makes from the ProHaus list price.

However, I learned from my general contractor that the T8 is currently being sold relatively cheaply with a lot of discount, which is why the surcharge could well be accurate. He even said that sometimes 42.5 cm bricks are sold almost without a surcharge compared to identical 36.5 cm bricks, since there is a very low demand for the 42.5 cm ones.

Today only with controlled residential ventilation.

As houses are built today, they are so airtight that no 'air exchange' takes place anymore. And the thing with the breathable house is simply nonsense. There are building materials/stones that have a certain moisture regulation. They absorb moisture when the air humidity is high and release it again when it decreases. However, it can only decrease if ventilation takes place. If the indoor air is not exchanged, the indoor humidity continuously rises because no air exchange occurs. Eventually, mold will form.

That is why you should always plan for controlled residential ventilation today. If you want to reduce the investment, you can also consider a decentralized solution with heat recovery. It is cheaper but somewhat less efficient.

I have a central system and the ducts in the ceiling.

It is ultimately the builder's decision how the house is built. I was against controlled residential ventilation from the very beginning. From my point of view, it is not needed. I prefer the double-shell, ventilated cold roof (and therefore do not need a vapor barrier on the upper floor), electric windows (with central control and rain sensor), and window seals can also be made as leaky as you want. Then I don’t have to worry about a recirculation hood in the kitchen and such nonsense. People who install ventilation ducts in their homes and have to worry about energy loss during normal ventilation are, in my opinion, really poor fellows.

Building dryers help against the greatest construction moisture. If necessary, you can even endure them after moving in if you’re in such a hurry and cannot leave the house standing over the winter. To me, the most ridiculous argument for installing controlled residential ventilation is to do so because of construction moisture.