Vinyl: Only glue on underfloor heating?

We also clicked the vinyl on the subfloor (with wooden battens). It becomes warm and was suitable for underfloor heating.

Elsewhere, it was spackled and glued (without wooden battens) about 1.5 years ago - now individual panels or the spackle are coming loose. It was installed there by a specialist company through the construction company.

I cannot say what is better. For us, installation by ourselves with wooden battens was the easiest.

We clicked - since insulation and reflection are applied below the underfloor heating, the heat can only go upwards. It may take a few minutes longer, but it does not affect the efficiency.

That is a misconception.

Then it’s now a case of one statement against another. Does anyone have evidence? I’m too lazy to look for it, since the train has already left the station for me anyway. But my flow temperature of 27-28 degrees suggests that the heating somehow does work after all... With two floors, the discussion is only about half the floor area (less if you subtract the stairs, kitchen, and utility room, as they are not heated), since the temperature in the ceiling doesn’t care where it goes. And whether the extra cost for bonding is still worth it... you would have to calculate that for a long time.

That is a misconception.

And that helps no one. Please briefly explain why, if possible with a source reference.

The room you want to heat has heat losses. These losses depend on the delta between the indoor and outdoor temperature. The task of the heating system is to compensate for these losses, or even overcompensate in order not only to maintain but also to increase the temperature. It must therefore emit more heat into the room per unit of time than the room loses to the outside. This amount is determined by the delta between the surface temperature and the room temperature. If you now insulate your underfloor heating against the surface (floor construction), you lose efficiency because you have to increase the supply temperature to get enough energy into the system. Additionally, the losses that your heating system has in other areas increase proportionally. This is naturally not super dramatic with click vinyl vs. glued, but it can of course matter. Exactly for this reason, there is the thermal resistance for all components (floor covering and not to forget the additional impact sound insulation), which gives an indication of suitability for underfloor heating.

The idea behind it is clear. But as already mentioned, for floors above the slab it doesn’t matter, since the energy stays inside the house and towards the (insulated) slab the (to be heated) screed is also insulated again. Visually estimated roughly 100 times more than the theoretical air layer under the click vinyl.

In short: where should the heat go if not into the house?

And even if here we heat the slab a few percent more than with gluing – the additional costs per square meter can never be recovered within maybe 20 years of floor lifetime!

Still, don’t get me wrong: gluing can be great. Marble floors or moor oak planks are as well...