Highly recommended product. Have grappled with high humidity in my solid walled detached house for over 5 years. The results have been areas of mould, streaming windows, fabrics that are cold to touch etc. Despite making efforts to address this including improving the heating, adding trickle vents to windows, leaving windows open, improving extraction in bathrooms/kitchen and running a dehumidifier 24/7 could never fully resolve the issues. Within hours of fitting this PIV unit the air quality in the immediate area of the diffuser was noticeably improved. After a week of running, humidity levels have consistently dropped by around 10% (measured at multiple points around the house) and the environment is hugely improved in all the areas where I suffered previously. On reflection, should've just bought a PIV system years ago. If you have a situation like mine, don't procrastinate any further - buy!