Controlled residential ventilation and disc valve - Passive House

Physically, it doesn't make sense because the air is colder than the room air - therefore, the mixing will never be optimal. I'm not surprised you hardly notice it - what should you notice anyway? It will somehow work and it's better than nothing.

And I don't really see the advantages - first of all, installation on the raw concrete ceiling is more difficult and requires good coordination between trades plus an appropriate floor construction. And then you have exhaust air in large slots in the walls, right?

Additionally, I always see the risk that something falls into the duct... children are quite experimental.

yes, that's right, my colleague also reported that they had found some of the things from the children there again.

For the ground floor, it has to go through the floor or the ceiling, right?
In the attic, you can still go through the loft.

And am I mistaken or aren't there also flat/oval pipes that can comfortably fit into the concrete ceiling? I think my colleague also has such pipes in his Pluggit system.

Flat ducts are installed on the raw floor, round pipes in the ceiling.

So if you are fast enough and with today's precast concrete slabs there is the possibility, do you then lay round pipes inside?

Flat ducts would then be used more likely if you do not have precast concrete slabs and therefore would have no chance to install flat ducts.

We have floor outlets on the upper floor; so far I can't see any disadvantages. The big advantage, from my point of view, is that the piping system is very simple: two floors, installation on the raw ceiling, core drilling downwards, supply/exhaust air at the ceiling there, and supply air in the floor upstairs, exhaust air on the wall quite high up.

All correct.

- To avoid expensive core drillings, you can punch holes directly in the precast concrete ceiling or order it with recesses. Be careful with too many openings concerning the direction of the ceiling's tension, or clarify this with the structural engineer. (Picture 1)
- Installation is no problem. However, you have to know the dimensions of the pipes quite early to adjust the height of the insulation under the screed or to be able to specify the finished floor height, for example, to window, entrance door, and stair manufacturers. (Picture 2)
- To keep the pipe length as short as possible (pressure loss), it is common for the inlets and outlets in the basement to be located in the ceiling. Also here, to avoid core drilling, simply attach a polystyrene block to the precast ceiling, as with all other openings, e.g., for drain pipes. (Picture 3 and 4)
- On upper floors, supply air below and exhaust air above. Used air usually rises upwards, and circulation is somewhat improved because the air is forced to move three-dimensionally. (Picture 5 and 6)

Some builders want the supply air, e.g., for space reasons, directly in front of the window. Then there is no other choice but to install the connection in the floor. Advantage: more space for furniture. Disadvantage: dirt can get inside because the plate valve filters are only at the outlets, and if curtains are planned, they will constantly be in motion.

Installing ventilation pipes in the ceiling requires coordination with the structural engineer, as cavities with undefined paths develop in the intermediate ceiling. They decide whether reinforcing the reinforcement at certain points is sufficient or if the entire intermediate ceiling needs to be more massive. One should then also adhere to the exact installation plan.

Depending on the contamination level of the system, there is the possibility to clean the ventilation pipes later. To my knowledge, a foam ball is blown through the individual pipes during this process. With a round pipe, the probability of a "hanger" is lower.

because the air is colder than the room air - therefore the mixing will never be optimal.

If air is heated at floor level during the heating period and then rises, fresh air supplied there should also rise and mix with the room air. The exhaust air valves installed at the top additionally enforce a crossflow.

And then you have exhaust air in large slots in the walls?

Correct. We have two exhaust air valves upstairs. One is in the "walk-in closet," there in a drywall (the only one upstairs), practical and uncomplicated. The second exhaust air valve is in the bathroom, where we needed a soffit. The result turned out very well and is not disturbing (neither visually nor space-wise). It is only a matter of a few centimeters. Alternatively, the wall would likely have had to be thicker (here 11 cm calcium silicate brick), which would have had to be planned in advance, but the developer did not think that far. (The floor structure and room height were considered, everything fits!)

Also, I always see the risk that something might fall into the duct

On the floor outlets are so-called design covers, rectangular stainless steel plates with many small round holes (sieve bottom). The children would really have to make an effort to put something in there. And even if? You just take it out occasionally. Our children certainly don't bother with it. Nothing falls in by itself.

The supply air openings are basically maintenance-free; the exhaust air covers must be cleaned of dust occasionally and then the filters attached inside must be cleaned or replaced.