I am a lung transplant recipient in CA, and anytime there's a major fire that affects the air quality I can't leave the house. The recent Camp Fire made it so that I have to wear a mask at home, even when I'm sleeping. I finally decided to invest in some serious air purifiers and bought the set of two, one for my living room and one for my bedroom. It makes an amazing difference! I can finally breath at home! Everything was easy to set up. The 45i in my living room is super intuitive; it has a sensor to let me know how high I should turn it and an auto setting that allows the machine to power down when it's cleared the air. Neither machine is very loud, about as loud as a fan on its highest setting. Easy to setup, easy to use, and easy to move. I'm honestly recommending this to all my friends because it makes such a huge difference in my ability to breathe.