Aqua Air EnviroSept 20 x 25 x 1 Inch Electronic Furnace Filter Panel 14 Pads EnviroSept Electronic Air Cleaner with One Air Filter Panel and 14 Air Filter Collector Pads. Whole House Air Cleaner Replaces 20 by 25 by 1 Inch HVAC Filters. Actual filter size is 19.5 by 24.5 inches. For residential or business forced air heating and cooling systems with a one inch thick furnace filter slot. This highly efficient, non-ionizing, non-ozone producing, electronically enhanced air filter system uses the concept of DIELECTRIC POLARIZATION to effectively remove sub-micron particles down to 0.001 micron in size. Note EnviroSept furnace filter air purifier units require two disposable PolyWool collector pads included . Plus 12 replacements in this package. Envirosept Electronic Air Cleaner 20 x 25 x 1 Inch for HVAC Use Information Electricity use Compare to annual use of your door bell. Less than 2 per year. Maintenance Requires disposable collector pads replacements as necessary. Size Determination See size printed on side of current filter. Installation Install pads, slip unit into 1 inch filter slot, plug into 120V AC outlet. Fan Setting Use Always On setting, not auto mode. Air cannot be cleaned if the fan is not operating. Changing Pads Change both pads monthly if someone smokes in the house. Tar and nicotine make pads sticky. Otherwise remove first pad in front where air enters ; shake second pad outside, rotate pad two to first position and install new pad in second spot. Odor Removal Reduces or eliminates many odors such as pet, cooking odors, and tobacco smoke. NOTE Enhance EnviroSept's operation by having dirty air ducts cleaned. Air duct cleaning removes construction dust and debris which EnviroSept cannot remove. This debris can be a media in which allergy and asthma triggers such as bacteria, dust mites, etc. grow. Operational Sounds Quiet operation. No snapping or discharge sounds unless collector pads are damp or overloaded with contaminants This item ships from a separate warehouse and may require extra time for delivery.