Energy efficiency of HVAC equipment suffers due to poor installation

According to a NIST research report, the benefits of improved energy efficiency ratings can go for naught if the refrigerating equipment is not installed properly.
The push for more efficient air conditioners and heat pumps aims to trim the 30 % share of residential electrical energy use devoted to cooling and heating in the USA. But the benefits of improved energy efficiency ratings can go for naught if the equipment is not installed properly, as verified in a recent study from the US National Institute of Standards and Technology (NIST).

The NIST research report “Sensitivity analysis of installation faults on heat pump performance” found that duct leakage, refrigerant undercharge, oversized heat pump with non-oversized ductwork, low indoor airflow due to undersized ductwork, and refrigerant overcharge had the most potential for causing significant performance degradation and increased annual energy consumption. Increases of energy use by 30 % due to improper installation practices seem plausible.

In surveys reviewed by the study authors, the majority of air-conditioning equipment evaluated in the field performed below rated energy-efficiency levels due to one or more installation faults.

Leaky air ducts emerged as the “dominant fault.” Refrigerant undercharge and incorrect indoor airflow due to improperly sized ductwork followed as the most significant cause of increased energy use.

Sizing, selecting, and installing HVAC equipment according to industry-recognized procedures is critical to ensuring energy efficiency.