I Want to Change the Condenser on My Home AC, What Do I Need to Do?

System SEER

• Central air systems have a life span of 15 to 20 years. The condenser/compressor unit normally wears out before the evaporator coil, located inside as part of the furnace structure. In an effort to save money, some homeowners might want to only replace the condenser and compressor, but that scenario presents several problems. For one, replacing the condenser and compressor and not the evaporator coil often leads to failure of the outside unit within two years. More importantly, however, are federal regulations that require split system components to have the same Seasonal Energy Efficiency Ratio. Beginning in 2010, all air conditioning systems must have a minimum SEER of 13. Homeowners must determine the existing unit’s SEER, if the evaporator coil is still operational.

Proper Sizing

• Bigger is not necessarily better. Air conditioning systems, which include the condenser capacity, are measured in tonnage. The bigger the unit, the more air it is able to cool. An air conditioning condenser that is too big for a home will cause the entire unit to cycle on and off frequently, resulting in blasts of cold air and decreased energy efficiency, all of which add stress on system components. In addition, oversized units are inefficient at removing humidity.

Heat Load Calculations

• To properly determine the correct size for a home central air conditioning system, a contractor or independent inspector should perform heat load calculations. Among the factors included in heat load calculations are the size and location of windows, as well as glass type, square footage of each room and the amount of insulation. Homeowners should not automatically install the same size air conditioning system in tonnage as what they previously had. Air conditioning systems, particularly in newer, larger homes, was often too big for the space it cooled. In addition, improvements such as additional insulation or newer, energy-efficient windows might have been added, decreasing the need for a larger system.

Installation

• Some savvy do-it-yourselfers might have the wherewithal to install an air conditioning condenser, but most don’t know where to begin. HVAC contractors have the knowledge and the personnel to do the job correctly. In addition, quality HVAC technicians will also be able to accurately perform load and other tests that will be used in determining the proper size of the unit. Homeowners should obtain quotes from three or four contractors before selecting one for the job.