Recessed pot for spotlights in ceilings with insulation

I can't provide a definitive statement on that, but if I were you, I would be cautious about installing the spots without a box, so that the insulation might directly touch them. As far as I know, LED spots (especially Retrofit GU10) do generate some heat, which is not as strong as with halogen or similar, but still needs to be dissipated. If this doesn't happen, at least the bulb's lifespan will suffer. If I were you, I would simply ask the electrician/architect/general contractor/whatever how this should be done. After a quick "Google" search, I'm quite sure that boxes are at least advisable. Alternatively, there are also spacers so that the insulation material does not touch the bulb. A little distance is sufficient.

We used Thermo-X boxes from Kaiser because we were also supposed to achieve airtightness. This was specified to us by the general contractor and also confirmed by two electricians.

I cannot prove it, my feeling would rather say that I use a box when the insulation is directly behind it, just like with us. Pressing the spots directly into the insulation would go against my instincts.

Best regards,
Christian

Well, with LEDs you certainly won't need a mounting pot because they don't get hot.

Not really? Then why all the heat sinks around them? Depending on the design, they do get quite warm and can easily melt the vapor barrier upon direct contact.

So I can definitely install them without planning even if there is insulation material or insulation foil directly behind?

No, you can’t... just use Kaiser ThermoX; that way you’re on the safe side.

How should I install the boxes in a closed ceiling? Then I have to work with the cover plate?

Cut the installation opening, insert the housing from below and fix it with the quick-lock. The housing is decoratively covered with the KAISER decorative cover and the luminaire.

What do you mean by that? Are you coming from above? If not, then cut a 120mm hole from below, insert the box, fill, paint, done.

I have to do it from below and with the aperture it looks lousy