I've had a problem with a NIBE 360P heat exchanger for over three years now and still the housing association and NIBE have failed to take action. Various engineers have been around and agreed that these systems do not work, are expensive, noisy and of very little benefit. Yet when their official report is made it's an entirely different story altogether. I'm fed up with being fobbed off, no-one will take responsibility, it is an absolute rip off!!!