LIRAST 150mm Single Room Heat Recovery Ventilation System - 6 inch Decentralised MVHR Unit - Wall Heat Recovery Fan with Ceramic Air Heat Exchanger - Heat Extractor Fan with Switch

Inexpensive compared to other similar products. Pretty noisy to be honest. Not sure how much heat recovery is taking place as the incoming air seems cool not warm at all

As heat exchangers go, this is cheap, but adequate for small rooms. However it is designed for a minimum of 300mm thick walls, something I'd overlooked when ordering and I had a job to fit it into my new extension which has only 275mm walls (and yes, its a new build that complies with building regs). This meant that the fins of the fan are very close to the heat exchanger and at first go the fan jammed -I had to pull the cover plate a few mm out from the wall to make it work at all. However, the worst part of this is the mimimal instructions -there is a schematic wiring diagram but no pictures of the actual switch connections, where you will find 8 small holes but no explanation of what wires go in which holes. With the aid of a multimeter I was able to figure out the switching arrangement (unlike UK standards, these switches have to be pressed upwards for on), but I was left with two unlabelled holes I assumed were for the neutral wires. When I tried to insert the neutrals, they didn't grip and fell straight out again -there is no metal lining in these holes so I had to connect the neutrals together with a connector outside of the switch. Then there is the switch itself which does not have the usual holes through which to screw to a back box. I had to press a couple of lugs out to release the metal part from the front and remove the switch plates -in fact take it into five pieces simply to be able to screw it to a box, and then reassemble it afterwards. I've never seen a switch like this before. Once assembled, it works, but you will need a fair bit of initiative to get it working.