An air conditioner is the outdoor unit that cools air and sends it to the indoor unit for circulation through your home. Indoor and outdoor units are designed to work together. When the air conditioner is properly matched with a furnace or air handler, you get maximum efficiency and longer system life.
Thermostats are extremely important because they are your interface and control system for your heating and air conditioning equipment. This is the device that will give you the information on what the equipment is doing and when it needs to be serviced, while allowing you to set the exact temperature and humidity you want to maintain in your home.