ᐅ Insulated drywall enclosure for controlled residential ventilation unit in the attic

Hello everyone,

I have two questions regarding the following proposal from our architect:
We are planning a two-story house with a pitched roof and a basement. He recommends installing the central mechanical ventilation system with heat recovery in the attic (this avoids breaking through the basement wall and having a "little tower" in the garden). However, the attic is intended to be outside the thermal envelope (insulation will be added on top of the concrete ceiling of the first floor). Since the attic can get quite cold without insulation, and according to him the ventilation system does not work well in rooms colder than 10°C (50°F), we are advised to build an insulated small room for the ventilation system on one gable wall inside a drywall structure attached to the masonry Poroton 49cm (19 inch) wall.

Question 1): Should I choose the gable side that is not above the kitchen on the ground floor with the exhaust hood, or do kitchen odors dissipate well enough over two floors so that you don’t end up pulling kitchen air into the ventilation unit in the gable?

Question 2): Are there any experiences with this approach of having an insulated small room? It seems the insulation on top of the ceiling would be left out in this area to allow heat from the first floor to rise into the small room. Is that sufficient to keep the insulated space warm enough just from the heat of the rooms below?

Looking forward to hearing your thoughts.

Best regards

Unfortunately, I can no longer edit: my husband thinks it should be referred to as "insulated" rather than "isolated." Sorry, I made a mistake. The small room will, of course, be insulated so that the heat from the rooms below is sufficient to keep it from dropping below 10°C (50°F) even in summer.

The procedure is not a problem. However, everything needs to be insulated—not only the mechanical ventilation system but also all the pipes located in the attic.

Hello Mycraft, thanks for your reply.

Is there any reason not to run the pipes for the mechanical ventilation system relatively quickly into the concrete ceiling? It is insulated above with an external insulation layer.

The small chamber can easily be made 2 meters (6.5 feet) wide, 2 meters (6.5 feet) deep, and 2 meters (6.5 feet) high. Then the pipes could be routed within the chamber into the concrete floor. Or is that too small for silencers and so on?

annab377 schrieb:

We are planning a two-story house with a pitched roof and a basement. He recommends installing the centralized mechanical ventilation system in the attic [...] should I choose the gable side,

Are we familiar with the overall house design? From "attic" and "gable," I assume this refers to a pitched roof over a rectangular upper floor (?)

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No, the house is unfortunately not here in its entirety. I also don’t have any drawings from the architect yet.
I just wanted to ask if there are already any experiences with such insulated controlled residential ventilation compartments in the attic? Unfortunately, I couldn’t find anything suitable through the search here.