Heat leaking into the cabin through vents. First, cabin filter replacement I found it covered in disintegrated black foam. Took it into the dealer under warranty and they confirmed heat was coming into vent system when set to cool, but I didn't have it fixed at that time. It has progressively gotten worse. The contents of the glove box gets hot and the only way to eliminate the incoming heat is to run the A/C, which doesn't help the fuel economy. I live in the desert, so this is a real pain.

There is no fresh air vent in this car. To get air that is not cooled or unheated you have to roll down the window or sunroof which is hard on interstate driving. I live in temperate climate and in spring and fall do not need heat or air but it is stuffy without either running. Poor design.