From http://www.greenbuildingforum.co.uk/forum114/comments.php?DiscussionID=9763

We have been in our house for almost a year now, tried to build to passishaus standards and despite plumber, electrician and MVHR installation problems (see previous discussions if clarification needed), the thermodynamic panel is one piece of kit that i cannot fault. There is a backup immersion fitted and has never been switched on and we have had 60 degree hot water every day without fail. I have seen the panel completely white with frost and still no bother with hot water. I am in no shape or form connected to any company that sells or installs the panels, but I have no problem recommending the technology.