Four functions, one amazing machine. Use functions individually or combine them. The air purifier removes allergens, pollen, dust, smoke and pet dander. The powerful, innovative airflow fan cools an entire room instantly. Variable heat settings allow for just the right amount of heat. The humidifier function has three settings - low, medium & high. Helps to protect your skin from damaging effects of dry heat. There is an empty water sensor for smart automatic power shut-off for the humidifier. The Heater shuts off automatically if the unit is tipped. A warning light indicates when the unit needs to be refilled with water. The True HEPA filtration captures 99.97% of particles down to 0.3 microns.