Same as what Ginger and Miss_Dee has said. Humidity affects the evaporative cooling system and when you have had quite a few days in a row of humid days it is not that effective. We have only had evaporative so I can't compare it to a split system. One thing I do like about the evaporative system is that I can have windows & doors open & if kids are going in & out of the house it doesn't matter if they don't close the doors properly.