I purchased 2 blue air purifiers. My first purchase was for my bedroom and then I purchased a bigger one for my living room. Immediately I noticed the air was crisper more clean feeling. I was suffering headaches on a daily basis when I arrived home from work and once I started running my air purifier my headaches drastically improved. The setting of low and medium on the machine are pretty quiet. The high setting is loud more like white noise which does not bother me at all. I love that this purifier offers a setting for nighttime that turns off the pretty bright blue light so it can run while you are sleeping. Very easy one touch operation. The filters are affordable and you can clean your purifier up to that point. I would gladly purchase more of these. My children have been requesting them for their bedrooms as well because they live the difference it makes.