On 02/01/2019 16:27, cf-leeds wrote:
I'm asking myself what degree of insulation the underlay is
providing. Maybe the piping is at 27 degrees, but the underlay must
be insulating the pipes to some extent. The the underlay is a
lightweight closed cell polyethylene material.


some but you have totally missed the point. The surface area of te floor
is much gfreater than the surface area of the pipes inside it: so the
heat drops massively anyway on its way to te floor surface

I've run my floor bare to test it with no thermostat flat out
overnmight. Even than it barely got above 30°C with a 50W/sq meter
estimated input at 50°C

add a bit of underlay and some engineered wood, and it wont exceed 27°C
at the wood surface.


--
A lie can travel halfway around the world while the truth is putting on
its shoes.