Does the need for a heat exchanger, etc make this system cost effective for heating a single room (5m x 5m) extension?

Due to the fact that the triple tube system has no oxygen barrier within the pipe itself, the heat exchanger is an essential part of the system, it is needed to keep the underfloor heating water seperate from the boiler water. More.

I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.