Can You Replace Just The Outside AC Unit?

image of an hvac contractor performing air conditioner replacement

Per the US Department of Energy, you should replace your HVAC system every 10 to 15 years. However, depending on the quality of your HVAC system and your maintenance schedule, your system may last well over 15 years. To extend the lifespan of your heater or air conditioner, you should schedule professional HVAC maintenance and tune-up at least once every six months. Preferably you should do this before the summer and winter seasons. Take note that in most cases, you may need to replace your entire HVAC system. When it comes to air conditioning units, many homeowners question “Can you replace just the outside AC unit?”. Here’s some more information on this topic.

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Can You Just Replace The Outside Air Conditioning Unit?

The simple answer is No. When replacing the outside AC unit in your home, HVAC experts recommend that you also replace the indoor unit. While this is entirely your decision, failure to replace both can cause issues such as reduced efficiency, regular failures, and increased cooling costs. Here are other reasons why you should replace both units at the same time.

Indoor And Outdoor Air Conditioner Coils Need To Match

According to the Air-Conditioning, Heating, and Refrigeration Institute (AHRI), outdoor AC units typically work with specific indoor units (air handlers). This means that your outdoor unit should match with the indoor one for compatibility and maximum efficiency. In other words, if you replace just the outside AC unit, you will end up with a mismatched system that is unlikely to meet your heating and cooling needs. Mismatched cooling systems tend to be inefficient, and therefore, cause a variety of problems. Some of these issues include reduced indoor comfort, premature system failure, and high operating costs.

SEER Ratings

image of efficiency vs cost depicting air conditioner with high seer rating
SEER is an abbreviation for Seasonal Energy Efficiency Ratio. It refers to the cooling output of an air conditioner over a cooling season compared to the energy consumption per year. The SEER of an HVAC system determines its efficiency. A SEER 13 rating is the minimum in the U.S., according to the US Energy Information Administration (EIA). For optimum efficiency, the outdoor and indoor AC units must have the same SEER rating. This means that if you replace the outside unit only, high chances are that the SEER rating will be different. Consequently, you will end up with a mismatched system and all of the problems that come with it.


The Phaseout Of R-22

As more people join in the journey towards sustainability, HVAC manufacturers are also adopting eco-friendly designs and materials to help save the environment. For instance, old HVAC models use the R-22 refrigerant, a harmful agent which contributes to the depleting of the ozone layer, as reported by the U.S. Environmental Protection Agency (EPA). Federal energy laws now require manufacturers to use the R-410A refrigerant since it is safer. Therefore, if you still use R-22 in your HVAC system, you should consider upgrading to the new refrigerant to enhance efficiency and promote safety. This means that if you only replace the outdoor one, it will be incompatible with the indoor unit.

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Air Conditioner Manufacturer Warranty

A new HVAC system comes with a manufacturer’s or factory warranty that covers breakdowns due to defects or flaws in factory-installed parts. However, if your outdoor and indoor units are mismatched, the manufacturer or dealer may void your warranty or deny you warranty repairs.

Premature Cooling System Failure & HVAC Repairs

image of broken condensing unit on air conditioner

A well-maintained and matched HVAC system has a lifespan of at least 10 or more years. On the other hand, a mismatched HVAC system tends to overwork to compensate for its inefficiency. As a result, this aspect shortens its lifespan considerably. Replacing one unit will cause the entire system to be inefficient, leading to premature system failure and frequent HVAC repairs. To avoid this, replace both the outdoor and indoor AC units at the same time.

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Benefits Of Replacing Indoor And Outdoor Air Conditioning Units

  • Save Money On Cooling Costs: Regardless of the SEER rating, a mismatched system will still have low efficiency. This means that it will most likely work extra hard to deliver the required cooling. This will increase energy consumption, eventually hiking your energy bills.
  • Better Home Comfort: Due to high efficiency, a well-matched AC unit will cool your home the right way and give you much-needed home comfort.
  • HVAC Warranty: As mentioned earlier, the manufacturer’s warranty will only be valid if your indoor AC unit matches the outdoor one. That said, replacing both units means that you will have a valid warranty on your new AC units.
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Tips To Maintain Your Air Conditioner

To prevent premature air conditioning system failure and premature AC replacement, use these tips to maintain your cooling unit:

  • Clean the HVAC air filter and replace it regularly
  • Make sure the fan is working correctly
  • Install a programmable thermostat
  • Ask an expert to inspect the condensate drain and unclog it, if necessary
  • Ensure your AC system is matched
  • Reduce HVAC system operation when not in use (adjust the temperature settings)
  • Perform regular HVAC checks
  • Schedule an annual air conditioner tune-up in the spring, right before summer


While performing these actions may not prevent your system from failing, it will most likely increase the longevity of your HVAC unit, increase efficiency, and lower your cooling costs. For proper HVAC maintenance and repairs, contact a qualified HVAC contractor that knows every detail concerning the maintenance of air conditioning units.


These are some of the reasons why you should replace your outdoor and indoor AC units at the same time. Take note that units from different manufacturers are considered mismatched, even if they have the same SEER rating. For proper matching of your HVAC system, you should hire a qualified HVAC contractor to replace your outdoor and indoor units.

Call McAllister Energy For Superior Heating & Cooling Solutions

McAllister Energy

McAllister Energy offers high-quality HVAC services in Camden County, New Jersey. We hire only the best professionally certified technicians who conduct superior heating and cooling services. Some of our HVAC services include HVAC maintenance, heating and cooling installations, repairs, ductless systems, and much more. All our techs provide accurate HVAC services on time, every time.

Our company guarantees affordable heating and cooling service rates. Our maintenance services can increase your home’s comfort, energy efficiency, and cost-effectiveness. We can also provide you with a highly energy-efficient HVAC replacement system that fits your budget. Your satisfaction is important to us, so all our work comes with a guarantee. Book a service appointment with McAllister Energy today. We provide free, in-home estimates.

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