Hi to all, I'm going to try to shorten this as best I can, but I would like to comment on air purifiers again since everyone has a concern regarding the ones that generate Ozone. Yes, too much Ozone can be harmful, but to get that much Ozone, you would have to go with the astronauts in outer space & LEAVE the space shuttle. I have 3 air purifiers, the first one I bought was Vaportek(optimum 3000) Air treatment system. The cost was $280, each time I change the 2 filters on it, it costs $25.00, depending on your household environment, will determine how often you have to change the filters, (I.e. smoking, how many pets, etc.) As a ferret shelter, I had to change the filters once a month, this gets expensive. I then went to the Honeywell Enviracaire Portable Hepa Air Cleaner, cost was $189, filters are approximately $35 to change, if you change them both at the same time. Again, this gets quiet costly since in reality, you have to change the filters once a month. I don't care what they tell you in the instructions, every 3 months does not do it. I then began research into the Ozone generating air purifiers(Alpine) I contacted the American Lung Association @ 1800-LUNG-USA, they would not say that these units were bad. They would only say that as long as you maintained a low level, it would not hurt you. Since you breathe Ozone every day that you go outside. I was mainly concerned about the ferrets, so I continued to research it. I spoke to several Homeopathic vets, I contacted the Health Department, division of Environmental Health & Engineering(if you contact them they will send you an entire package on healthy air/indoor air) I have had major exposure to mold and mildew along with some other contaminants containing carcinogens & never want to go through that again. Back in 1993 we were renting a place and had to move from there because of the mold inside the walls and bacteria in the air conditioner. People, you haven't begun to imagine what you are breathing on a daily basis inside your own home. There are places that do testing, usually government buildings , etc. for sick building syndrome, you can have your air tested in your home, it is costly, but well worth it. I paid $550 for the testing & found out the air was slowly killing us. Of course we moved. I continued my research into the Ozone purifiers and decided that as long as the Ozone produced was regulated and that there was a sensor and a shut off if it ever did get too high, then this was the best way to go. I do not have to buy filters every month, I have no odor in my house as long as I keep the filters clean & in the 3 years that I have had it, I have been sick one time with the flu. I know that I also have an actual purifier, the ozone helps to cut down on mold, mildew, and other bacteria. There is a book( Prescription for Nutritional healing, by James & Phyllis Balch) this book recommends the Alpine XL-15 to maintain good air quality in your home, pg. 253 under Environmental Toxicity, you can read all about contaminants in your home air. On page 254, under recommendations, they have listed the XL-15 Air Purifier to remove animal odors, bacteria, dust, pollen & smoke. I know how frustrated you feel in your search for a good air cleaner because I have been there, I will take a little dose of ozone every day compared to mold, mildew (these two can literally kill you) and everything else in the air. Really search well, as I said, call the American Lung Association, the Health department and the (EPA -The inside story, A guide to indoor Air Quality) (this book will scare the heck out of you) to get all of the booklets they have on Indoor air pollutants and air quality. Then make your decision. I researched for a year. As far as a deionizer, I'm not sure what that is, but an ionizer is negative ions that sort of zap the dust particles and drops them from the air so that you do not breathe them. You can also go to www.ecoquestintl.com to get info on the Alpine/Ecoquest Unit & see all of the other products they have. they have A/C filters, Water purifiers, mattress covers and many other items. I am not giving you all of this info to sell you a unit, but to try and help you out. I do not blame anyone for being concerned , I was there myself. Good luck to all of you in your search and hug those fuzzies! Sue See my auctions at: http://showcase.auctiva.com/ferret [Posted in FML issue 3253]