Honeywell W8600F Owner's Manual page 17

The regular furnace filter collects mainly large,
The electronic air
visible particles that reach the filter. Its main
cleaner vs. the
purpose is to protect the furnace and air
standard
conditioner blower. The electronic air cleaner
furnace filter
collects these large particles, plus many of the
smaller, mostly invisible particles. Its purpose is
to reduce indoor air pollution as well as to
protect the blower, air conditioning coils and
heat exchanger.
15 69-0756B—2