Where can I find practical information on Air Handlers and Central Air Compressors? I am purchasing a house with these features and I am familiar with the traditional heating and cooling equipment. Thank you.

Traditional heating and cooling has a compressor and condenser outside, an air handler and A coil inside. If you have gas, there is also a gas heater assembly. No central "air" compressor, it is a Freon compressor. Air handler is the inside fan. Is this a heat pump or gas? In many parts of the country, gas or oil heat and central air conditioning are standard.