ᐅ Underfloor Heating – Wet System and Dry System

Hello everyone,

We are currently gathering several quotes for our house construction. Generally, it’s already difficult to compare the offers. However, we are puzzled about one point. We are planning to install underfloor heating with an air-source heat pump throughout.

- Three developers say they install the underfloor heating as a wet system.
- One developer (the most expensive one) says they use a dry system, which is much faster for heating up and cooling down and is of higher quality (and more expensive).

From online sources and one developer, we have learned that wet systems are generally used in new builds, while dry systems are more common in renovations and with timber ceilings.

What surprises us is that especially the most expensive (and supposedly very good) developer is offering the dry system.

Could you help us understand which system is better or what the advantages and disadvantages are?

Basically, there are two types of systems: wet and dry. In the wet system, the heating pipes are embedded directly in the screed and surrounded by it, whereas in the dry system, the pipes are located in the insulation layer beneath the floor covering. For new builds, the wet system is usually preferred because the floor is being installed for the first time, making the heating installation simpler and relatively cost-effective. Additionally, the heat transfer and storage provided by the heated screed is advantageous. In contrast, for older buildings and renovations, installing a wet system would involve significant effort and costs, which usually only makes sense during a complete renovation. Therefore, dry systems, where the heating pipes are placed directly under the floor covering in so-called dry screed panels, are the best choice here. For new construction, however, I would prefer the wet system.

Toffifee88 schrieb:

We are just really surprised that the most expensive (and actually very good) builder offers the dry system, especially in that case.

Most likely, this saves them time, reduces build-up heights, and eliminates the entire screed trade. This way, they can complete the construction much faster than others and increase their profit.

Toffifee88 schrieb:

... that is much faster when heating up and cooling down...

And that is the biggest disadvantage of dry construction systems. You don’t want temperature fluctuations, and ideally, you shouldn’t have to control the room temperature. The goal is to have an even temperature throughout the house and a high thermal mass. Since this is rarely achieved in new buildings through thick ceilings or heavy walls anymore, at least the screed should provide some thermal storage capacity.

It still won’t get too warm: because the floor is ideally only a few degrees above the air temperature, it cannot release any more heat if the air temperature rises suddenly (due to sun or stove).