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Effect of Installation Faults on Air-to-Air Heat Pump Performance



Piotr A. Domanski


Numerous studies and surveys indicate that typically-installed HVAC equipment operate inefficiently and waste considerable energy due to different installation errors (faults) such as improper refrigerant charge, incorrect airflow, oversized equipment, leaky ducts. This study sought to develop an understanding of the impact of different faults on heat pump performance installed in a single-family residential house. It combined building effects, equipment effects, and climate effects in a comprehensive evaluation of the impact of installation faults on a heat pump’s seasonal energy consumption through simulations of the house/heat pump system. The study found that duct leakage, refrigerant undercharge, oversized heat pump with nominal ductwork, low indoor airflow due to undersized ductwork, and refrigerant overcharge have the most potential for causing significant performance degradation and increased annual energy consumption. The effect of simultaneous faults was found to be additive (e.g., duct leakage and non-condensable gases), little changed relative to the single fault condition (e.g., low indoor airflow and refrigerant undercharge), or well-beyond additive (duct leakage and refrigerant undercharge).
IEA Annex 36


air conditioner, commissioning, energy conservation, fault detection, heat pump


Domanski, P. (2015), Effect of Installation Faults on Air-to-Air Heat Pump Performance, IEA Annex 36, [online], (Accessed May 25, 2024)


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Created January 20, 2015, Updated February 19, 2017