Ventilation system in the warm summer

Cooling or at most buffering via the floor has many disadvantages. Cold feet, cold stays at the bottom, dew point, no dehumidification, etc.
Better to have a proper air conditioning system. Better controllable, dehumidification, cool air is properly distributed, powerful…

I agree with you. But it only cost me a plug at Vaillant and works surprisingly well for us. However, so far only in dry heat.

What I find very interesting is how it will be with the humid and warm weather forecasted for next week.

You can always do better with cooling, it also works to a limited extent with an air-source heat pump. What doesn’t work at all is cooling through controlled residential ventilation. All agreed.

I have already spent a few decades in various houses and, incidentally, I am the owner of a Jugendstil villa optimal for permanent air exchange, which does not have to deal with things like insulation, underfloor heating, or cooling.

Of course, you can always badmouth everything you don't know. I don't have cooling? No problem, just claim that you always have cold feet because of it. Very old building fabric? No problem, just claim that modern houses all have a lousy indoor climate. It's like the fox who can't reach the grapes and then says: They are probably sour anyway.

For me, moving into a modern house with a central ventilation system and underfloor heating/cooling was such a huge leap that I say: Never, never anything else again. Sure, if I were in a different climate, I would get a proper air conditioning unit - I know the humid-warm climate in the Rhineland very well, for example, and there I definitely want to have the aforementioned advantages of a proper air conditioning system. Here it works excellently, calmly, and you don't notice it in a positive sense at all - until you notice the difference.

Here for this climate: Never, never anything else again. And I myself have several houses for comparison.

I’m glad I don’t live in a submarine or a plastic bag. Single-family house built in 1978, decent windows, properly insulated, currently 21.7 degrees in the well-ventilated bedroom. I believe that too much insulation is not conducive to a pleasant living climate

I think insulation is less the problem here. We’re talking about relatively small temperature differences between inside and outside. During the day it’s about the same or slightly warmer outside, at night a bit cooler. A problem is more likely that the walls, even in solid construction, mainly consist of air and hardly buffer any heat. And of course the large window fronts that are common nowadays. In the new residential area, there are no big trees to provide shade, and many expansive terraces collect the heat directly in front of the window.

I also know houses with the technology you used. It is cheap to implement but not real air conditioning. Therefore, it is not comparable. You just shouldn’t install something like this with the wrong expectations. If you know the limits and disadvantages, it’s not a problem. Currently, it’s almost still single digits at night here. So the cooling doesn’t even have to run yet. Our house also doesn’t get that warm. Ventilated cladding, thick concrete, automated shading (you can see through from the inside), house overhangs, and a real cooling system. We operate with -4°C coolant temperature.

IMHO the problem is rather (and here we approach the topic again) that in new construction very often more research goes into the perfect steam cooker for the kitchen than into the construction method, heating, and ventilation technology. The infrastructure should simply be as cheap as possible to purchase. The money is then preferably spent on fancy Q3 walls and gigantic bathing landscapes. Of course, everyone can set their own preferences and if someone perceives a rough plaster as a "90s tenement" or a "cow barn", well, fine, their decision, but then please don't complain that money can't be used elsewhere anymore. What follows, I have experienced myself: I lived for ten years in a poorly constructed apartment building where these alibi fans were installed in the wall that you have to put in to achieve the air exchange rate but should never actually use. My conclusion from that: ventilation is crap. I was simply wrong there, because bad ventilation is crap but good ventilation is wonderful!

And it goes on like this, it's a mixture of "seeing a horrifying example and generalizing from it" and "badmouthing what you don't have and/or don't know." When modern houses are labeled as submarines and plastic bags, then probably everything is true at the same time. Only since I have had a house with good ventilation have I noticed how abysmally bad the air in non-ventilated houses/apartments is.

For work, I lived for a long time in Southeast Asia, and when the monsoon comes, the aircon runs constantly to bring the indoor humidity to somewhat bearable levels. Nobody there cares about air outlet temperature or draft freedom. Now I don't have a monsoon in the Alpine foothills at 550m, and therefore the underfloor cooling makes the difference between "unpleasant" and "pleasant." It's not even really there, it just quietly does its job. No, neither in the Rhineland nor in Southeast Asia would I see my underfloor cooling as a substitute for aircon. But if the choice is "no air conditioning at all" or "not always completely optimal air conditioning," then my choice is clear.

If you know the limits and disadvantages, it’s not a problem.

Does anyone really want to know that? Even if it gets complicated and the generalizations ("submarine") are thereby shaken? Probably not. When I built, I spent the first year bringing myself up to date on the state of the art through conversations with civil engineers, supply technicians, heating contractors, etc., and discarded many of my prejudices ("ventilation molds!") in the process. Letting go of well-maintained prejudices hurts.

House projections

Here too: who actually does that? I looked at the old farmhouses and they all have roofs extending far beyond the south side. Good shade in summer, lots of sun in winter. So I tormented my general contractor for weeks that I wanted a wide balcony projecting over the window fronts on the south side. Result: in summer, not a single sunbeam hits the glass areas, in winter the whole living room is bright.