[This review was collected as part of a promotion.] I had bought the Hot + Cool older version years ago and loved it, especially the cooling function. I swapped that one out of my bedroom for this one with the newer de-NOx filter and while the heating & cooling remain the same (but excellent), the new filter does seem to provide better breathing thus far. I have asthma and I’m particularly sensitive to air quality this time of year and I’ve noticed a slightly better increase in my lung function with this new machine. For reference I live in an urban area with very high pollen count in spring, along with my three dogs, and I genuinely feel this contributes to my improved breathing. I struggle to sleep without the machine on as it feels stuffy otherwise. And the “white noise-like” and cooling effect are bonuses!