ᐅ Retrofitting Underfloor Heating – A Decision Guide

Hello experts,
We have purchased a ground-floor apartment built in 2004 and want to convert the current central heating system from district heating to underfloor heating.

Since we have no experience with such renovations, I wanted to ask for your advice here.

Which underfloor heating system should we choose? Screed milling or a dry system with prefabricated panels?

If it’s the dry system, which manufacturers are recommended? I’m quite overwhelmed by the many options available, such as Roth, Knauf, Kermi, Thermisto, and others. It would be really helpful to hear from your experience which one we should go for.
The apartment has a ceiling height of 2.5 meters (8 feet 2 inches), and we definitely want to preserve as much of that height as possible, even if we go with a dry system.

I would be very grateful for any recommendations or tips.

bedhes_ schrieb:

We have purchased a ground-floor apartment built in 2004 and want to convert the current central heating system from district heating to underfloor heating.

If I understand correctly, you have bought a condominium. Is that right? If so, do you even have permission to access the screed, since as far as I know, this is common property.

Exactly right, the approval from the homeowners’ association (HOA) has already been granted, so there is no issue.

bedhes_ schrieb:

Which underfloor heating system should we choose? Screed milling or a dry system with prefabricated panels.

If it’s the dry system, which manufacturers are recommended? I’m really confused because there are so many manufacturers out there (Roth, Knauf, Kermi, Thermisto, etc.) offering these systems. It would be very helpful to hear from your experience which one we should go for.

First of all, it’s important to know the heating load. For that, you need the supply and return temperatures of the heating system.
With those, the spacing of the underfloor heating pipes is calculated and so on.
After that, it really doesn’t matter which system you use. It’s roughly like choosing between a blue or red car.
Milling has the advantage that it doesn’t change the floor height. I would only recommend a dry system if the old screed is being removed (or if you’re doing a proper wet screed directly).

What I’m personally interested in is how you handle the connection and calculate the heating costs. Do you use heat meters before mixing?