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Compressors, Condensers, And Other AC Parts To Know Before Your Installation

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Installing an air conditioner is not easy, which is why it's wise to hire a professional to do this work for you. A professional HVAC contractor can recommend a good AC unit, make sure it's connected properly, and install a compatible thermostat and central fan. But while they will do most of the work, it is still a good idea for you to have a basic understanding of what they're doing. Knowing the basic components of an AC system will help you out in this regard.


The compressor is the main AC unit that goes outside. It's usually rectangular in shape and sits on a concrete pad. The compressor has refrigerant lines running through it. As the refrigerant runs through these lines, it gives off its heat. In doing so, it discharges heat from inside your home.

Evaporator Coil

The evaporator coil is an indoor component of your AC system. Your HVAC contractor will usually install it on top of the furnace or next to the furnace. This component is where the refrigerant contracts and is cooled. Air passes over the refrigerant lines in the evaporator coil and is cooled.

Central Fan

The central fan is the component of your AC system that actually blows out the air into your ducts. It usually works with both your furnace and your air conditioner. If you're only having your AC replaced, your contractor may leave your current central fan in place until you're due for a furnace replacement. If you're having both your furnace and your AC replaced, you can bet that the contractor will also replace your central fan.

Main Plenum

The main plenum is the part of your ducts that connects directly to the central fan. If you have the central fan replaced, your AC contractor may also need to replace the main plenum. The main plenum needs to be shaped in such a way that it can be connected to your central fan, and every central fan is a slightly different shape.


Yes, the thermostat is a part of your AC system. It controls how long your AC runs and how cool it makes your space. If your thermostat is more than a couple of years old, your HVAC contractor is likely to replace it alongside your air conditioner. Older thermostats are not always compatible with new AC units.

Now that you understand what basic parts make up your AC system, you'll have a better understanding of what your AC contractor is talking about when they discuss your upcoming installation. For more information on central air conditioning installation, contact a professional near you.