How to "eliminate" air from underfloor heating in a drywall system?

Hello dear community,

I am currently studying underfloor heating systems and will probably choose a dry system due to the low installation height. However, the problem with the dry system seems to be that the heating output is comparatively poor compared to the wet system (I have seen several calculations showing that the dry system is about 40W/m², while the wet system is about 27W/m². That is almost a quarter to a third worse... o_O)

Now I have also read that this is mainly because of the air between the heating pipe and the usual aluminum sheet. Wouldn't it be possible to somehow "remove" the air? One possibility would be to apply thermal paste in between. Has anyone ever tried that? Would it be inadvisable because of potential problems that one might not initially think of? Otherwise, I am seriously considering trying it out. The costs should eventually pay off if the heating runs a few percent better for a few years.

Are there perhaps other ways to get rid of that annoying air?

Unfortunately, I cannot offer you a solution for the specific problem. But for the same reasons, I also considered drywall for a long time until I found out that there are also "wet" systems with a low build height. I then chose those and am very happy with them. How much clearance do you have?

I have 6cm. However, the surface is quite uneven, so thin layer will probably not work, as I understand it...

I had between 4.5 and 8. Sometimes in one room. I had to adjust it to a maximum difference of two cm before the screed was laid, but it worked. Since I am not allowed to name websites, names, or similar here, you can send me a PM with your email address if you are interested in the manufacturer.

For me, the biggest advantage of a "proper" underfloor heating system is the greater heat capacity. I can easily turn off the heating at night for two months a year and heat up the screed properly during the day (using photovoltaic power). This is not as efficient as continuous heating, but it costs almost nothing. There are no noticeable temperature differences in the house either.

Thank you, that is of course a really crucial tip regarding heat storage. I also have a photovoltaic system :)