ᐅ Is a Central Ventilation System Really Necessary?

This is not a matter of belief... I believe it’s better to have a decentralized system than none at all, as that is one of the biggest mistakes homeowners make today...

However, I share the same view as €uro and prefer centralized systems... Construction experts are usually found on the opposite side—that is, supporting decentralized solutions...

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

klblb schrieb:
This topic is quite emotionally charged. Ask three homeowners, and you’ll get five opinions.

Here’s my take:
It’s not necessary. We build with humidity-controlled fresh air supply units (from aereco) and exhaust ventilation in the bathroom (upper floor) and guest toilet (ground floor). And no, you won’t be sitting in cold drafts with a scarf and jacket in winter. Our architect has been using these systems for many years. So far, there have been no complaints from residents. No mold either. The initial investment costs are much lower than with a mechanical ventilation system with supply and exhaust ducts in all rooms. The ongoing costs (heating the cold air with the described solution vs. electricity, maintenance, and filters for mechanical ventilation) will probably balance out.

What does that mean? You’re only starting to use it now. So you don’t have real firsthand experience yet? Just what your architect tells you?

@RFR: Correct. The architect has implemented this in numerous construction projects, and the feedback has been as described.

@ klblb - Am I understanding correctly that you have a decentralized mechanical ventilation system without heat recovery? Could you explain in more detail—how many units for how many rooms, how do you manage without wall openings, and what was the total investment?

We have an appointment this afternoon at the "ventilation office" in Bernau, where I would like to inquire more about such an option. So far, the decentralized mechanical ventilation systems with heat recovery that have been suggested to us, considering the number of rooms (living-dining-kitchen area, ground floor extra room, guest bathroom on the ground floor, utility room, 3 bedrooms in the attic + converted loft), involve between 6 and 8 units with heat recovery plus 3 to 4 exhaust units, which results in costs hardly any lower than a central system...

I believe it largely depends on whether you build with or without insulation. We plan to build with 36.5 cm (14.4 inches) brick walls WITHOUT insulation, aiming for KfW 70 standard. The opinions of the last three developers we consulted were consistent. Approximately 90% of houses built without insulation are constructed without a ventilation system, as it is generally not considered necessary for this type of construction. One developer even installed a ventilation system in his own house but does not recommend it unless it is necessary, because the outside air drawn in becomes very dry during winter due to the preheating.

This is not my personal opinion but reflects the statements of the last three developers.

You were given incorrect information. Ventilation has nothing to do with the type of insulation. It must always be installed airtight.