I got this air purifier because we have two cats and I'm extremely allergic to them. On top of that, my husband is slightly allergic to them and has asthma. Our health has been going downhill but we refuse to just toss our cats out. The GermGuardian has been great so far. We've only had it a few days but I noticed the difference after the first morning. Typically I wake up with a lot of mucous in my throat but within 24 hours, I was waking up with far less of it. It's only gotten better as time has gone on.