The Honeywell F300 Electronic Air Cleaner is designed to work with gas, oil, and electric forced warm air furnaces and with compressor cooling. It can also be used with heat pumps if the filter is changed regularly to prevent excessive pressure drop. The F300 Electronic Air Cleaner is not recommended for applications where pressure drop may be critical. CFM: 2,000; Description: Electronic Air Cleaner With Post-Filter; Duct Size: 20" x 25"F300E: Includes cabinet, access door, solid state power supply, two electronic cells, two metal mesh prefilters, and two media postfilters.