We are extremely satisfied with our Winnix Zero Pro. This was bought to improve air quality in our bungalow (which is near a busy avenue), a function it performs admirably. Particularly impressive is the low level of noise when running in all the speeds bar turbo (which is never needed anyway). In fact, on sleep mode, it is barely audible. This appliance has given us peace of mind that we are not breathing in polluted air and have to admit that it seldom runs on the red setting (poor quality air) for very long before it cycles back through to 'blue' (good quality air). Finally, we would like to commend the excellent customer service we received, from checking that the order was authentic and not a fraudulent activity on our account, to being informed of dispatch (very prompt) of both parts of the order.