What to Know: Common Causes Impacting HVAC System Performance

Several of the most common causes of low system performance affecting SEER are:

  1. Supply and return air duct leakage.
    Leaks in the duct system can lead to uncomfortable operation and high energy consumption. return air leaks in the return ducts cause the system to draw in hot, humid air from the attic that overloads the fan coils ability to properly condition the air. The Energy Gorilla is alive and well in your attic!
  2. Lack of proper charging during start up.
    Improper charging of the air conditioning system can cause the unit to experience longer than normal run cycles. Lack of proper charging can also affect the unit's ability to remove humidity. These cycles cause the energy consumption to increase, and it also can cause damage to the compressor through lack of oil entrainment and lack of suction gas to cool the compressor valves. Lack of proper charging techniques will often cause a slow (but sure) failure of the system components. The Energy Gorilla is alive and well in your attic!
  3. Undersizing of the duct system.
    The low-ball mentality of saving a few bucks on the ductwork is one of the largest contributors to the Energy Gorilla being well fed. Undersized return air ducts causing the fan coil unit to struggle to get enough air to properly evaporate refrigerant. The fan struggles to move enough air, the energy costs rise and the SEER begins to drop. Undersized supply air ducts impacts the fan performance curve producing high static pressure, high air velocity, and noisy air delivery.
  4. Lack of maintenance.
    Dirty filters, low efficiency filtration, dirty duct systems. Did your system get installed with a low end filtration system, or no filtration at all? When was the last time the system filter got changed or cleaned? Proper maintenance is required for your system to operate efficiently and provide a long and healthy life. Installation contractors should stand behind the installed systems and offer service plans and extended warranties. Annual maintenance, the cleaning of coils, replacement of filters and overall system performance should not be forgotten.
  5. Insulation.
    Current energy codes require minimum insulating values for duct systems installed after 2004. A lack of insulation in the duct system will lead to a lack of system performance and added energy costs.

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