There is no proof that it actually cleans air.it makes a lot of noise and we need to change the filter every other year, the cist of product is 25000 and the cost of filter+service is 5570. I think it is quite expensive. Moreover, had to make number of calls to get it done. The first technician assigned for this work didnot have the faintest idea what an air purifier was. The second technician check and said need to change the filter but had no.clue when and where they are available. Phathetic service. Better to use airpurifying plants than these stuffs!!