Thank you for the input. I have been thinking of getting another air filter machine for our house. I do not have allergies but it looks like this one addresses other things such as bacteria and pollution etc. There is another one on the market that makes the same claims made by Austin Air Systems. We currently have a Honeywell which is well rated but not claiming to be medical grade air cleaning etc. Anyway thank you. We have a lot of farm pollution in the air in our part of Iowa and the usual allergins, mold etc.