When replacing an outdoor unit, do I need to replace the indoor unit too?
This would be dependent on the age and condition of the indoor unit. We recommend if the age of the outdoor and indoor unit is more than 15 years, replace both units. Of course, some systems are designed to operate as a complete system, and both units have to match. The efficiency rating is based on the entire system and replacing the entire system ensures the system will be reliable, efficient and meet tax credit requirements.