When old air conditioners have to be replaced the question is what to replace – the entire air conditioning system or the failed parts only. The answer is the entire air conditioner needs to be replaced.
There are two main parts in an air conditioner – the evaporator and the condenser. You’ve never seen the evaporator. It quietly sits inside the ductwork and absorbs heat from inside air into the refrigerant. The condenser, the other main part, sits outside of the house and looks like it’s doing all the work. Actually, it’s only doing half the job. The condenser squeezes heat out of the refrigerant into the outside air. Most of the time the culprit is the condenser since this is where all the wear and tear happens. You might be tempted to replace the condenser only.
Condensers and evaporators are not good at all at adjusting to each other. If the evaporator absorbs too much heat from the house, the condenser will overheat. If the evaporator doesn’t absorb enough heat, it will freeze itself. The only
way make sure an air conditioner will work properly is to match its two main components – the evaporator and the condenser.
It’s fairly easy to match components when you install a new air conditioner, as you can see at
ARI Reference Number page. However, it’s much more difficult to match the components of aging systems. Virtually all the systems that may require condenser replacement today were designed to work in 6, 8, or 10 SEER air conditioners. All the air conditioners that are on the market today are 13 SEER and up. Good luck matching 10 SEER (or even 8 or 6 SEER) evaporator with 13 SEER condenser.
This is why; if you have to replace your old air conditioner, replace everything.