I would love to say that I have an idea of how this product works, but I never got a chance. When I opened the box it looked like someone else had already had it. The cord was not packaged like it would be from the manufacturer. I unwrapped the whole thing and picked up the water tank part only to find numerous cracks and a chunk of the tank missing. The chunk that was missing was not even in the box. Obviously another customer purchased it and returned it. Returns must not be checked for damage. This was extensive damage, easily noticed with a quick once over.Consumer reports rated this humidifier as the best and I have been waiting to try it. I think I will return this one and order from another supplier