With energy efficiency a leading factor in the optimization of furnaces for the home, the best modern models are condensing furnaces. By capturing and condensing water vapor in the air, condensing furnaces take advantage of the tighter, more closed system that characterize modern homes and yielding ever better energy conservation. But a condensing furnace may require fine-tuning the intake and exhaust of air to balance levels of humidity in the home.
When your heating and cooling system’s fan is set to ‘on’ it operates continuously. The compressor continues to periodically cycle on and off automatically to cool and dehumidify your home when the fan is set to ‘on’ or ‘auto’ on your thermostat. The difference between the two settings is that with the fan ‘on’ and continuously circulating the air, the temperature stays more even throughout the house by clearing out pockets or layers of static, warm air.