When One Unit of an AC Fails, It’s Best to Upgrade the Whole System
With split-system central air conditioning and heat pump systems, it’s not unusual for one of the two units (indoor or outdoor) to fail before the other. Most often, it’s the outside compressor/condenser unit that gives up before the inside evaporator/air handler; this is because the one outside is exposed to the elements and thus experiences more wear over time. As often as this happens, it’s not surprising that homeowners frequently find themselves asking whether they can just replace the outside unit, or if they have to buy a whole new split-system AC.
In most cases, the answer is emphatically that it is NOT a good idea to just replace the unit that has failed.
Your AC Equipment Was Designed to Work Together
Split-system ACs and heat pumps, the most common home HVAC units at work today, are engineered and designed to work together as one cohesive system made up of separate units. This results in optimum performance and energy efficiency. While it may be feasible to match a new outside unit with your old evaporator/air handler, you can’t expect the same sort of output that you’d get with a properly matched system.
If you choose to replace just the worn out half of your split-system AC or heat pump, you’re giving up the benefits of major design advances in HVAC technology in the years since your system was originally installed. Installing a completely new ductless mini split system will give you the full benefit of those advances — you won’t gain those benefits in performance and efficiency if you just replace one of the two units.
Energy efficiency – the amount of cooling you get from the electricity that’s put into the split-system AC – is the main area where you can expect to lose out on technological advancements if you don’t upgrade to a new, matched system. If you match a new, outside (or inside) unit with your old inside (or outside) unit, you will not benefit from the high efficiency that most modern systems boast. This means that you’ll continue to pay higher energy bills while also paying for half of a new system. You won’t be able to recoup some of the cost of the new unit from the lower electric bills you’d get if you had bought a completely new, matching system.
Your Old AC Unit Likely Will Fail Soon Anyway
If you choose to buy just one half of a new split system, matching your old inside unit with a new outside unit, you’re just deferring the replacement expense until that older unit itself fails in a year or two, leaving you with the same dilemma you had before. If one of the units fails, you can bet the other one won’t be far behind. And in a year or two, you might have trouble finding the exact unit that would match perfectly with the “new” unit you bought a year or two ago.
Do yourself, your home comfort, and your utility budget a favor: when one side of your split system AC or heat pump fails, make the wise decision to upgrade the whole old system with a new, high-performance, high-efficiency HVAC system. You’ll end up saving money on the matched system, since buying the units separately, a year or two apart, likely will cost more than if you had bought them together. (If something truly unexpected happens to your outdoor unit years before its expected lifespan is over, like a tree falling on it, or it being damaged in a flood, then you can justify only replacing the damaged unit. But if the failing unit is even 75% of the way through its expected lifespan, it’s a better investment to replace both at the same time.)
For these and other reasons, replacing your indoor and outdoor AC or heat pump units at one time is the best decision. It’s one system, and it’s meant to be purchased that way. If you’re here in the Cincinnati area, and you have questions on the best course of action in replacing or repairing your HVAC system, give us a call. We specialize in taking the headaches out of heating and cooling issues, so you can focus on more important parts of life.