This Holmes air purifier has two cartridges that need to be replaced(I have found) every 4 months. It does above average on our 10 x 20 room. On high power it tends to be a little noisy, but on medium settings is just slight background noise. We have 3 cats and it has been a struggle to remove the dander and hair that seems to have been common-place until we have used this unit. We give it a two thumbs up for air quality with using this. Recommend purchasing it.
I purchased this air purifier unit for our living room area. I was able to see the difference right away. The filters do not need to be replaced as often as I thought. This has saved me some money. I later went and purchased to smaller units which I have in each of mu boys bedrooms. Helps to keep there rooms clean and fresh.
I have several pets and this Holmes air Purifier works really good. I bought one for my living room and I have 2 smaller ones for the bedrooms. Everyones allerigies are so much better with this purifier.