The Honeywell F114 commercial ceiling mounted media air cleaner is a self contained commercial air cleaning unit. It is typicaly used in a restaurant or bar where smoking is an issue. Normal maintenance is to replace the Honeywell F114A and F114C prefilters every month, the HEPA filter every 10 to 24 months and the CPZ filter every 4 to 12 months. Heavy smoking bars should use the more often version of those dates.