ᐅ Single-Pipe Heating in Niches: Relocate, Insulate, or Replace?

Hello everyone,

I am currently renovating my condominium built in 1986.
The apartment currently has a single-pipe heating system, and the radiators are installed in recessed heating niches.
Due to thermal bridges in these heating niches, mold has naturally developed.
Therefore, I have the following questions:

Should the radiators be moved forward and the niches be bricked up?
If so, what is the best way to do this?

Alternatively, should the radiators be left as they are and the niches insulated?

Or would it be better to remove the entire screed and install a new underfloor heating system?

(User error made)

simimimi schrieb:


Mold has naturally developed in the heating niches due to thermal bridges.

"Naturally?" If the radiators are warm, moisture shouldn’t form, right?

Following the advice of an energy expert, we sealed up our heating niches with Ytong blocks and installed new radiators in front of them. (That was quite some effort.)
We also replaced the pipes since they dated back to 1970 and developed a leak in one spot during the work. This was fairly manageable because we were able to reroute most of the pipes through the basement rooms and precisely position them by running them through the floor.

The radiators now stand awkwardly in the room and (of course) take up more space.
But the suggestion made sense to me, and I assume it is genuinely efficient from an energy standpoint.

Mold should not be taken lightly 😉 It “must” be removed!

The room temperature in the apartment is still around 22-23°C (72-73°F), even now that the heating is completely turned off due to renovation work. Therefore, I usually don’t turn on the radiators in the apartment at all. This is why I have the problem with thermal bridges in the recesses.

simimimi schrieb:

That’s why I have the problem with thermal bridges in the recesses.

You have two issues: mold and poor insulation.

Since you probably won’t get rid of the mold without modifying the recesses (either closing them off or insulating them), I would recommend closing them off. As far as I know, insulation needs to have a certain thickness, so you can avoid the trial of “is it enough or not?”

In both cases, the pipes will need to be altered. If the radiators aren’t relocated completely, it’s not that much work.

Closing off the recesses will definitely solve both problems.

The issue with the add-on is that it involves a single-pipe heating system, and one installer said that this supposedly doesn’t work.