Has anyone seen the report from Purmo recently which suggests that there is a 15-25% improvement in efficiency when using rads over UFH, due to the slow response and overshoot engendered in an UFH system.

It is not written purely from a HP perspective but does make reference to them and the study was carried out in Sweden so presumably may have included some systems using HP's.

I'd be interested in others views of the survey, as it is not specifically aimed at HP's its relevance to the technology is perhaps suspect, but it does allege that the difference in COP due to higher temps with rads is offset agains the efficiency losses due to overshoot and lack of control.

Cynically too it's published by a rad manufacturer!

It is downloadable from here: http://www.purmo.com/en/clever/cleve...ions-movie.htm