My reason for buying this air purifier I've tried other air purifiers and they just did not work in the area that they clean wasn't large enough this one is large enough clean 700 ft.² of my apartment the reason why I bought this one the air ducts in my apartment are so dirty and dusty the management here will not clean them so I bought this air purifier to take care my problem so far so good I do suffer from allergies and this has been a blessing for me hope this can help others out