In addition to cool and fan only modes, this versatile unit also has Dry mode to remove excess humidity from the room without additional cooling. In October 2017, the Department of Energy implemented a new test procedure to determine the BTU rating of portable air conditioners. Apr 29, 2012 · My Amana PTAC air conditioner Model No PTH123E35AXXXAB has the following thermostat problems: in winter, in HEAT mode with the thermostat set at 58, the unit seldom cycles with room temperature in the seventies. Now, in COOL mode and the thermostat set at 60, the unit cycles with the room temperature in the seventies. Dry mode works in very much the same way as cooling mode, except the fan speeds are much, much lower. This means the air is moving more slowly over the coil, allowing for more moisture to be removed. While running a unit in dry mode may actually reduce your indoor temperature slightly, it's an effective way of removing humidity without converting your home into a frozen tundra.