Most updated central air conditioned homes have a new air conditioner split system meaning the ac is broken up into parts.
Airflow of a evaporator coil in a attic hvac unit.
As the condenser fan spins it attempts to draw air across the condenser coil and through to the evaporator coil.
The condenser coil on the outside unit is just as important as the evaporator coil on the indoor unit.
Your evaporator coil is an a shaped web of copper coils that sits inside your indoor ac unit.
Most homeowners never actually see the evaporator coil because it is covered by a metal case that is usually in an indoor closet or attic.
So why put an hvac system up in the attic at all.
An outdoor unit which houses the fan condenser and compressor and an indoor unit which holds the evaporator and fan.
Attic hvac systems save space.
The evaporator coil can be a magnet for dust debris and other contaminants this is because it is installed within the airstream of your hvac system.
So if your evaporator coil has sprung a leak and your unit uses r 22 it could get very expensive to replace the coil and then recharge your unit with more r 22.
Well mainly it s a way to save space.
The external surfaces of the evaporator coil that face the airflow in the duct are accessible and cleaning is generally within the skill level of most do it yourselfers.
The evaporator coil is the part of your ac system that actually cools the air before it is blown into your home.
It s critical to have your evaporator coil inspected annually and most dyi ers are more than capable of cleaning the external surfaces facing the duct airflow.