ᐅ But should you install a controlled residential ventilation system?

Hello everyone,

We are in the final stages of planning our house; the floor plan is set, and the detailed construction planning will take place soon. It is a prefabricated house built with a timber frame construction and a prefabricated basement on a slope, meaning the front part of the basement is fully exposed above the slope.

So far, we have excluded the topic of mechanical ventilation with heat recovery, partly due to planning concerns (we are doing everything ourselves from the rough plumbing and electrical installation stages) and partly for cost reasons. However, in recent weeks, we have started to reconsider this, mainly for comfort reasons.

Long story short: Our question mainly concerns the routing of the ductwork, which would partially be installed within the floor structure. So far, we have planned for a floor buildup of 15cm (6 inches) on the ground floor. However, if we were to increase this to 18cm (7 inches) as our house manufacturer suggests, the clear floor height would decrease from 245cm (8 ft) to 242cm (7 ft 11 in) on the ground floor. This would bother me a bit. We cannot change the floor-to-ceiling height due to the zoning plan restrictions (maximum eave height fully utilized).

Now the question is: Is it really necessary to plan for 18cm (7 inches) because of duct crossings, or are there alternatives? For a suitable floor plan (here is our current one: https://www.hausbau-forum.de/threads/efh-in-Hanglage.12265/page-3#post-90366), could the ducts be routed only within the walls? And which mechanical ventilation system with heat recovery would you recommend for a living area of 180m² (1,938 sq ft)?

Thanks in advance for all the information!

Uwe