So why put an hvac system up in the attic at all.
Airflow of a evaporator coil in a attic hvac unit.
In fact the evaporator coil often fails due to issues with the condenser coil.
However if dust or dirt contamination is so extensive that the inside coil surfaces are affected too schedule a more extensive heavy duty cleaning procedure with your hvac.
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.
As the condenser fan spins it attempts to draw air across the condenser coil and through to the evaporator coil.
R 22 is so expensive in fact that most hvac professionals would advise replacing the entire unit not just the evaporator coil if you have a refrigerant leak anywhere in the system.
The condenser coil on the outside unit is just as important as the evaporator coil on the indoor unit.
Well mainly it s a way to save space.
An outdoor unit which houses the fan condenser and compressor and an indoor unit which holds the evaporator and fan.
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.
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.
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.
Most updated central air conditioned homes have a new air conditioner split system meaning the ac is broken up into parts.