However, some MVHR units do have a mini compressor and reversible heat pump to include heating or cooling down to the inbound air. http://twin-dragon.net/__media__/js/netsoltrademark.php?d=www.pdc.edu%2F%3FURL%3Dhttps%3A%2F%2Ftufnellparkairconditioning.co.uk%2Fair-conditioning-repair.html