Hi, I am planning on building a dedicated HC room as part of a new house build project in Austria, -15 to +30C is common . Heating will be underfloor heating using deep bore ground source heat pump (or maybe air source) and solar. I have heard that the underfloor heating pipes can also be used for cooling, which I might need due to many large south facing windows in the house. Does anyone know how effective this passive cooling method is? Is some sort of air circulation required? Is condensation a problem. ie is it any good?? I should not need air con due to the improved insulation and the concrete construction. The work office is a also new build and they have installed ceiling mounted passive cooling radiators. Cold air sinks. So, is this the laest thing in cooling?