Residential HVAC Maintenance for Energy Efficiency

Proper maintenance is essential to achieving persistent energy savings with a high-efficiency HVAC system. Commonly, issues such as improper refrigerant charge, coil fouling, and clogged filters decrease a system’s performance from its rated efficiency. However, with proper maintenance, the detrimental effects of these problems can be mitigated.

The refrigerant charge in a residential air conditioning system must be set correctly to achieve desired equipment performance and life. Improper refrigerant charge can result in shortened equipment life, higher running costs due to diminished capacity causing longer runtimes, and decreased system efficiency. A study performed by Davis Energy Group, Inc found that system efficiency can be diminished by over 10% with a 20% refrigerant overcharge.

Evaporator and condenser coil fouling is also a source of diminished HVAC efficiency in residential systems. Dirt and debris clog the coils, leading to degraded heat transfer capabilities, and higher static pressure drop, causing higher fan power draw. According to a study by Ramin Faramarzi, P.E. of Southern California Edison’s Technology Test Centers, coil fouling was found to reduce system EER by as much as 35%.

Dirty air filters increase fan power consumption, because the fan must overcome the extra static pressure across the clogged filter media. Clean filters are easier for air to pass through, and thus require less fan effort to move air through the HVAC system. The department of energy cites savings of 5% – 15% just by replacing a dirty filter.

It is important to perform proper maintenance on residential HVAC systems to ensure that peak system performance is possible. Taking steps to address the problems listed here could result in energy savings of up to 35%, and will lengthen equipment life. Also, ensuring that the refrigerant charge is correct, the coils are clean and free of fouling, and that the air filter is clean will help to ensure that the rated capacity of the equipment is maintained.

Department of Energy HVAC maintenance tips for lower energy bills: http://www.energy.gov/energysaver/articles/home-cooling-strategy-lower-energy-bills

HVAC Energy Efficiency Maintenance Study by Davis Energy Group, Inc.: HVAC_EE_Maintenance_Final

Presentation with Ramin Faramarzi’s findings on HVAC maintenance technologies: HVAC Maintenance Technologies