12-14-2014, 10:20 PM
I would think that a job that size, serviced on a regular basis would fall somewhere between .09 - .12 per sq ft. Of course this reduced price would be valid only if they have it serviced quarterly or more frequently. Otherwise, the price for "as needed" cleaning would need to be the same rate you've been charging all along (which I assume is higher that .09 - .12).