Dew point sensors for underfloor heating: how and where to install them?

So we are very satisfied with our combined underfloor heating and cooling. The dew point does not change between floor and ceiling. However, on some days you do indeed have to additionally dehumidify to create a comfortable climate. The art of usage lies in not letting the room temperature reach an astronomical 28 degrees at all. We keep it constantly at 23-24 degrees in summer, so the absolute humidity remains low. Flow temperature then accordingly at about 20 degrees. Dew point sensors can certainly also simply hang in the room and then calculate the corresponding values. However, it must be taken into account that the floor coverings must not insulate! So parquet or also floating laid design flooring with insulating impact sound insulation are not recommended. It should also be considered that it does not only depend on the surface temperature, but also on the flow temperature itself, if this is not meticulously insulated, which is often not possible in distribution boxes due to sight glasses, valves, and so on. And even there you don't want condensation fallout, which can lead to mold.

It is simply the easiest way for most people to keep the house 1-2 degrees cooler without having to invest much if a [Fußbodenheizung] is already installed. I have not seen cooling sails on the ceiling in any single-family house yet. I think that says a lot about the costs involved. An air conditioning unit would probably be the only alternative, but for many it is again too expensive or not feasible at all. For us, the interior plastering work is finished, and our heating engineer said that it is too late now to install an air conditioning system; that would halt the entire construction until all components are delivered and installed. Apart from additional chiseling work for electrical wiring, condensate drainage, etc. That is why cooling via [Fußbodenheizung] is unfortunately the only option for us now without incurring immense extra costs.

I don't think FBK is that bad either. We have it in the office and it takes out quite a bit of heat. When you can't air out the heat at night (office, noise, urban heat island, ...) it definitely helps quite a bit. Of course, you still have to provide shading, and you can't really compare it to an air conditioner.

Thank you very much for your feedback. Since a heat pump with underfloor heating is coming anyway, the passive cooling function would be possible for a very small additional cost. However, it is clear that this is not as effective as a proper split air conditioning system.