I don’t know why life is full of choices, but it is. If you have ever faced the dilemma of choosing to replace only the outside condenser unit of your air conditioning system, while a sales person pressures you to replace both the condenser and the indoor coil at the same time, you know what I’m talking about. I faced that decision and had to muddle my way through the many factors involved without the benefit of advice from a professional I could trust. It only complicates matters if you are in a position of having had no air conditioning for three days in the middle of summer. That situation might send you over the edge, but you have to think logically to work your way through this problem.
Obviously, one of the most important factors in this decision is money. Can you afford to do it right now? A condenser is substantially less expensive than a replacing both parts of the system. If you do not have the funds available, or the access to funding, your decision is a simple one. If you’re like me, you also have real first-world issues with replacing a perfectly good portion of a unit just because you have to replace a broken part of the unit. The cost involved is huge and the voice of my miserly father reverberates through my head. But is there more to it? Yes.
Is there a warranty involved? Most manufacturers won’t warrant the system if you only replace some parts.
The cost of installation to replace one major part now, and another major part later can be substantial, and you need to factor that into the overall cost. It could all be done at the same time which would save those extra installation charges.
You can never achieve the efficiency you hope for by replacing one old part, but not the other, which is another cost consideration you need to ponder because it may have a noticeable impact on your monthly cooling costs. It certainly can’t ever help.
Regulatory issues associated with coolant may have the largest impact on the costs. Old units use coolants that have been phased out or will be phased out and future costs may be substantially higher to install newer units, which must also be compatible.
It is always better to install a matched system, with the most energy efficient operation you can achieve. If you compare your A/C system to a vehicle you might better understand the logic if you imagine replacing your engine but nothing else. You have a new engine, but the rest of your old car is only going to last so long. And a new engine does not a new car make.
One last bit of advice, develop a relationship with your A/C service provider so that you have someone you know and trust advising you when you have to make these very complex decisions. They will have much more knowledge of the subject than you, and by developing that relationship you will foster trust and can have faith in their advice.