Replacing only the outdoor unit (the condenser) of an AC system might seem like a cost-saving measure, but it’s not typically recommended. The outdoor and indoor units are designed to work together as a coordinated system, and mismatching the components can lead to decreased efficiency and performance. Furthermore, manufacturers may not honor warranties if the system is not properly matched. For the most part, it’s best to replace both the indoor and outdoor units at the same time to ensure compatibility, optimal performance, and maintain the warranty.