A typical central air conditioner is actually made up of two main components - the indoor air handler that contains the blower fan and evaporator, and the outdoor cabinet that contains the compressor and condenser coil. When one half of this dynamic duo conks out, you'll need to replace both halves.

Considering the average cost of replacing a central A/C system, that could be a rather hard pill to swallow. However, the cost of replacing only half of your cooling system could cost you more than you'd realize.

Mismatched A/C Systems Offer Poor Performance

Both halves of your current central A/C system basically work together as a single unit, making it important for both halves to be installed together as a pair. Each half is perfectly matched in terms of refrigerant type, cooling load and other essentials. Replacing just one half of this team seems like a penny-wise move, but it's often foolish for a variety of reasons.

For starters, installing one brand-new half of a split central A/C system to an older half often results in degraded performance. The remaining older half of the system may struggle to keep up with the upgraded performance of the newer half, resulting in an overworked component that becomes failure-prone in a short amount of time.

That is, if you can get the two mismatched halves of your central A/C system to operate at all. For instance, if the older half of your system still uses R-22 refrigerant, then you won't be able to link it with newer components that rely on the latest in hydrofluorocarbon (HFC) refrigerants. Mixing two different refrigerants in the same system can quickly ruin both halves of your central A/C system.

Mixing and Matching Won't Save You Money

Replacing only half of your A/C system seems cheaper than a complete replacement, but deliberately mismatching your system could cost you plenty. According to HomeAdvisor, the majority of A/C repairs throughout the U.S. cost between $167 and $495. Since a mismatched system often needs increased maintenance, you could find yourself spending thousands of dollars keeping a poorly matched system alive – money you could have kept in your pocket by purchasing a properly matched central A/C system.

While working overtime just to keep up with normal cooling demands, mismatched central A/C systems also consume far more energy than a properly matched A/C system would. The resultant energy waste can add up to more costly utility bills throughout the year.

Worst of all, a mismatched system can throw a wrench in your A/C replacement schedule. Replacing half of a central A/C system with a projected 12 to 15-year lifespan after 8 years of service won't extend the older half's service life. When the older half reaches its end, you may find yourself paying more to have both the newer and older half replaced with a properly matched system, even if the newer half still has a few years left in it.

Mixing and Matching Also Affects Your Warranty

In most cases, your central A/C system's warranty is only effective when you use matching A/C equipment. Using mismatched components may void your warranty, since the manufacturer can't be sure whether a defect or failure was limited to just the newer half of the system or caused by the older half. It's also yet another reason why most manufacturers are only willing to sell central A/C systems as matching pairs.

Even if the warranty was split between the two halves, the warranty for the older half may expire well before the newer half's warranty. Having only half of your A/C system covered under warranty could prove tough when it comes to covering impromptu repairs.

For more information and assistance replacing your system, contact a professional service like HomeSmart From Xcel Energy.