What Impacts Air Conditioner Efficiency and Performance?

Impacts on AC efficiency

Have you ever noticed that an estimated miles-per-gallon (MPG) on a car has two estimates – a city MPG and a highway MPG. Why? It may be because a vehicle’s actual fuel economy can vary depending on driving conditions and operational factors. 

The same goes for your air conditioner’s Seasonal Energy Efficiency Ratio (SEER) stated on the system components. If the installation or usage varies from the standard testing conditions1, the performance and efficiency of an air conditioner may be impacted.


The Split System Match Game


Similar to an automobile’s standardized MPG testing, an air conditioner’s efficiency is tested within set laboratory conditions with properly matched system components. Manufacturers identify a unit’s SEER value through standardized testing and algorithms prescribed by the Department of Energy.2 The separate elements of your split cooling system must be compatible and in proper working condition to function at the certified SEER level in your home.

According to the Air Conditioning, Heating and Refrigeration Institute (AHRI), “Improperly matched indoor and outdoor units can create undue stress on a cooling system, dramatically reducing efficiency.”3 AHRI suggests that mismatched systems are at least 30 percent less efficient than matched systems.”4

The AHRI’s free Directory of Certified Product Performance provides public information regarding certified reference numbers, SEER ratings, and compatible equipment. A licensed professional HVAC contractor can provide you with a Certified Reference Number or a Certificate of Certified Product Performance to verify a matching system and its SEER rating. If you are considering replacing just the outdoor portion of your cooling system, often referred to as the condenser, be sure to discuss compatibility and efficiency rating with your HVAC contractor.


Energy Costs and Efficiency Ratings


Even if your HVAC components are compatible, a high-efficiency air conditioner is just one aspect to efficient operation. Standards dictate that higher SEER air conditioning units be more energy-efficient than lower SEER units. Yet, when your cooling system is not being maintained as recommended or simple home energy-efficient solutions are ignored, your energy bills may still be higher than you would like.

To keep your central cooling system at peak performance, a licensed professional HVAC dealer should perform routine maintenance services. During an inspection, your dealer may identify any airflow problems, system leaks, coil issues or potential concerns that could impact your system from operating at peak performance. 

Professional HVAC maintenance services may include the following actions to keep your cooling system at peak performance:

  • Checking for adequate air flow
  • Looking over outdoor condenser coil  and indoor evaporator coils
  • Checking outside and inside refrigerant lines and inspect for leaks
  • Inspecting indoor drain lines and pans
  • Checking external and internal electrical connections
  • Checking operation of indoor blower components
  • Lubricating internal and external motors, bearings and other moving parts
  • Inspecting Exterior Fan


Homeowners should also keep in mind additional conditions that may impact energy costs. These factors can influence the ability of your cooling system to perform at its designed efficiency level. Some conditions include, but are not limited to:

  • Improper system installation
  • Thermostat or control system location or settings
  • Undersized or leaking ductwork
  • Inadequate level of insulation and non-insulated construction methods
  • Leaking or drafty windows and doors
  • Dirty or improperly installed air filters


The Future of Energy Efficiency


Innovative technology and the push for higher energy-efficiency has played a big role in the transformation, effectiveness, and popularity of higher efficiency cooling systems. In 2015, the U.S. Department of Energy changed from a national minimum SEER standard to regional standards. Currently, the minimum SEER values for air conditioners depends on location and ranges from 13 or 14 SEER.

Yet, air conditioner manufacturers continue to pursue individual technologies that collectively may improve overall cooling system efficiency. Advancements, including refrigerant, variable-speed drives, advanced thermostats and control systems, and additional mechanics that simplify installation may continue to impact the energy costs associated with cool, indoor comfort.

To discover current HVAC technologies available that may improve the energy efficiency of your home, discuss the various options and potential cost saving with your licensed professional HVAC dealer.

AC Efficiency

1 Environment Protection Agency. Vehicle and Fiel Emissions Testing. n.d. https://www.epa.gov/vehicle-and-fuel-emissions-testing. 18 April 2017.
2 Department of Energy. Appliance and Equipment Standards Rulemakings and Notices. n.d. https://www1.eere.energy.gov/buildings/appliance_standards/standards.aspx?productid=48&action=viewlive. 18 April 2017.
3,4 AHRI. HVACR Replacement Guidance. 15 January 2013. http://www.ahrinet.org/Contractors-Specifiers/HVACR-Replacement-Guidance.aspx. 12 April 2017.