Thanks so much for introducing us to the XL 15 air purifier, as it has changed our lives dramatically. About 2 years ago when we first purchased this wonder-machine, we had a lot of painting going on in our kitchen. Every day we were forced to endure an “itchy” and instable environmental – I remember being able to feel the air particles go up my nose. However, when we flipped switch of the XL 15, within 1 hour, my nose was HAPPY. It felt so good, so wonderful, truly an amazing conversersion of the air quality.