Is a central ventilation system absolutely necessary?

This is not a religious war... I am of the opinion that a decentralized system is better than none at all... because that is one of the biggest mistakes builders make today...

however, I see it like €uro and favor central systems...
The building expert is always to be found in the other camp... that is, with the decentralized ones...

So everyone has their opinion... the original question was whether a "central controlled residential ventilation system" is necessary, and I have commented on that...

The topic is ideologically very charged If you ask 3 builders, you will get 5 opinions.

So here is my opinion:
It is not necessary. We build with humidity-controlled supply air elements (from aereco) and exhaust extraction in the bathroom (upper floor) and guest WC (ground floor). And no, in winter you will not be sitting with a scarf and jacket in cold draughts. Our architect has been installing these things for many years. There have been no complaints from the residents so far. No mold either. The investment costs are much lower than with a controlled residential ventilation system with supply and exhaust ducts in all rooms. The running costs (heating the cold air with the described solution vs. electricity, maintenance, and filters with controlled residential ventilation) will probably balance out.

What does that mean? You are only just starting to build with it now. So you do not yet have real experience yourselves? Only what your architect tells you?

: Correct. The architect has implemented this in numerous construction projects and the feedback is as described.

@ klblb - Am I understanding correctly that you have a decentralized controlled residential ventilation system without heat recovery? Can you explain that in more detail - how many devices for how many rooms, how do you manage without wall holes, total investment?

We have an appointment this afternoon at the "Ventilation Office" in Bernau, where I would like to inquire more precisely about such an option. What has been proposed to us so far in terms of decentralized controlled residential ventilation systems, with heat recovery for the number of our rooms (living-dining-cooking, ground floor extra room, guest bathroom ground floor, utility room, 3x rooms attic + converted attic space) was between 6 and 8 devices with heat recovery plus 3-4 exhaust devices, and that results in costs hardly lower than a central system...

I think it strongly depends on whether one builds insulated or uninsulated. We want to build with 36.5 cm brick WITHOUT insulation with Kfw 70. The opinions of the last 3 developers were unanimous. About 90% of the houses built without insulation are built without a ventilation system, as it is not necessary with this construction method. One developer even installed it in his own house but does not recommend it if it is not necessary, because the air drawn in from outside becomes very dry in winter due to preheating.

This is not my own opinion but reflects the statements of the last 3 developers.

zovima15

You were told nonsense. Ventilation has nothing to do with the type of insulation. They must always be executed airtight.