I live on the third floor of an apartment complex, meaning I have two neighbors beneath me who essentially heats my apartment.
I want to install floor heating through a water heat pump and I have read it's recommended to insulate at least 25cm (10"). This is not possible, as the space between the floors is only 20cm, and it's wise to leave 25% free. I also dont know what the 25cm is based on, maybe it's only for ground floors because 25cm insulation is a lot.
I am considering leaving as it is right now, without insulation, as I believe that will trap the neighbor's heat and I wont enjoy their "free heat". Or am I missing something?