I have been running my air purifier 24/7 for almost 2 months now. I haven't had any problems with this unit.
1) Really cleans the air- after just a WEEK of use, the outer (carbon) filter was covered in dust! Disgusting, but I'm satisfied to know that wasn't in my lungs. I vacuum the filter once a week.
2) HEPA filter. Although I can't actually "see" what it is catching, I know it is helping my air quality! I live in Utah where the inversion pollutes the air on a regular basis during the winter. This air purifier gives me peace of mind, knowing that when I come home I am in a clean air environment. Not only that, but it catches dust mite allergens, pollen, plant spores, bacteria, fungi, mold, smoke, dust..... We are definitely sleeping better at night, not waking up with the usual "stuff" that you have to clear out of your throat in the morning... catch my drift?
3) UV light- peace of mind that the germs that are caught by this thing are killed.
4) Catches SMELL (carbon filter)- I am used to smelling leftovers when I let my pots/pans soak in the sink overnight. Not anymore! I know this works because one time we went out of town overnight and turned the unit off. When we came back, our apartment smelled like soaking dishes/leftovers. A smell I'm glad to be rid of using this unit!
1) When I first got this unit, the lowest setting was pretty quiet. It is noticeably louder now. However, at this setting me and my husband are still able to sleep with the unit in our bedroom at night. AKA not too loud for sleeping (and I used to sleep strictly with earplugs for 2 years straight, so that should tell you something!). Because the fan got louder, I rate this product 4/5 stars. I hope it doesn't continue to get louder. I will update if it does.
2) When we first used it, it did have a "new" or plastic/carbon smell to it. I imagine this was the carbon filter. The smell was gone by the second or third day.
I recommend this product. It is the best Air purifier/HEPA filter you can get for this price range. Obviously if you spend more money, you can get a much better product that will cover more square footage.
**IMPORTANT- the 22" model can be used up to 155 sq. ft. The 28" model can be used up to 193 sq. ft.
Buy according to your needs. AKA, measure the living space you want to use this unit in. In bigger rooms you will need MORE THAN ONE UNIT if you want this product to work effectively. Just an FYI.