Mismatched indoor and outdoor units cause serious problems. Replacing just one unit may void the manufacturer's warranty. If the unit is less than five years old, it may still be under warranty. In that case, you can probably replace just the outdoor air conditioning unit. Unfortunately, in most other cases, it's probably best to replace both indoor and outdoor units.
Replacing just one unit will result in an inefficient system, which in turn will lead to frequent repairs and early system failures. The Seasonal Energy Efficiency Index (SEER) is the cooling power of the air conditioner in a cooling station compared to its annual energy consumption. In addition, the air conditioning valve, which controls the flow of coolant from the coils, will have to work more. However, replacing the outdoor air conditioner alone will cause the unit's SEER rating to decrease, causing an inefficient system and everything that goes with it.
