The dry anti-mildew function is a post-operation setting where the indoor fan continues to run for a few minutes after the unit is turned off. This dries out the moisture on the evaporator coils to prevent the growth of mold and mildew inside the air handler. This feature is especially popular in our Cooper&Hunter series to eliminate that "musty" smell sometimes associated with air conditioners. Keeping the internal components dry is a key part of long-term maintenance for any wall mount unit. It works in tandem with our humidity control settings to provide the cleanest air possible. This is a small but highly effective way to protect your health and your HVAC investment.