Forward temperature floor heating cooling function

What supply temperature do you set your underfloor heating to when you want to use it for cooling? (We have a geothermal heat pump with passive and active cooling functions). Do you use a fixed temperature or a temperature curve depending on the outside temperature?

Manufacturers of heat pumps recommend a flow temperature of approximately 20 °C for the cooling function. At an air temperature of 25 °C and a relative humidity of 70 %, the dew point is not reached until a temperature of 19 °C. On average, the relative humidity in the house is between 50 - 55 %, so a dew point undershoot does not occur.

The upper humidity of 65 % should not be exceeded according to EN 814 T1 - T3 and DIN 1946.

Cooling through surface systems is part of a gentle tempering system, whose application is enabled by the excellent thermal insulation commonly used today. The best thermal insulation and a floor heating system adapted to the additional cooling function ensure flawless operation. When using surface systems for cooling, it is important to limit the surface temperatures or water temperatures to avoid condensation. One option is to specify a minimum flow temperature. For floor heating systems, the minimum flow temperature should not be chosen below 18 °C. In practice, for residential buildings in cooling mode, a flow temperature of 18 - 20 °C and a return temperature of 21 - 23 °C are assumed.

Otherwise, the topic of dew point monitors – have you had any installed? Then you can handle the temperature more "actively."

Thank you for the answer!

1) In my manual, a supply temperature of 8° can be seen in an illustration, see picture. (It is an Ecoforest Ecogeo Compact C3 3-12KW HTR EH)

2) For the dew point temperature of 19°, which must not be undercut, is the supply temperature decisive or the floor temperature? In other words: Is the supply temperature allowed to be less than 19° as long as the floor temperature is >19°?

3) Can I see it on the floor if the dew point is undershot?

4) Regarding the dew point monitor, I found the following in the manual, see picture

1) In my manual, there is a diagram showing a flow temperature of 8°, see picture. (It is an Ecoforest Ecogeo Compact C3 3-12KW HTR EH)

In midsummer, take a bottle of beer out of the fridge. Then you know what happens on and in your floor.

2) For the dew point temperature of 19°, which must not be fallen below, is the flow temperature decisive or the floor temperature? In other words: Is the flow temperature allowed to be lower than 19° as long as the floor temperature is >19°?

First of all, the floor temperature, because the moisture coming from the indoor air nests on/in the floor. In the end, however, it will be more or less the same, since the floor temperature approaches the flow temperature.

3) Can I see on the floor if the dew point is undercut?

No. It is like with old buildings. You only see the damp walls when there is mold or the plaster crumbles off the walls in the basement.

4) Regarding dew point monitors, I found the following in the manual, see picture

That means nothing to me. Have suitable sensors been installed? Where is the measurement taken – only at the flow or correctly in the screed? How many sensors have been installed? I know the pragmatic application from other undisclosed discussion groups here (Geisha discussions), where no user keeps the flow below 18 degrees. Actually, 18-20 degrees are always used without condensation problems occurring. BUT: Many users then complain about "disgusting" air because although the air is cooled in the rooms, the humidity (relative) increases significantly. So, basically a cool sauna. Dehumidifying only works with an air conditioner. I myself once ran 20 degrees in summer but stopped cooling quite soon, since this year summer didn't really occur enough to justify cooling. There would have been enough electricity from photovoltaics. But since I also have wooden floors everywhere, I did not want to go any lower. Dew point monitor is not installed.