United States. The push for more efficient air conditioners and heat pumps aims to cut the 30% share of residential electric power consumption dedicated to cooling and heating in the U.S.
But the benefits of improving the energy efficiency rating may not work if the equipment is not installed correctly, as verified in a recent study by the U.S. National Institute of Standards and Technology (NIST).
The NIST research report, "The Sensitivity Analysis of Installation Failures in Heat Pump Operation," finds that duct leaks, insufficient refrigerant load, large heat pump with small ducts, low indoor airflow due to undersized ducts, and refrigerant overload, they had the greatest potential to cause significant performance degradation and increased annual energy consumption. Increases in energy consumption by 30% due to improper installation practices seem plausible.
In surveys reviewed by the study authors, most air conditioners evaluated in the field exhibit levels below the energy efficiency rating due to one or more installation failures.
Leaky air ducts emerged as the "dominant fault." Insufficient refrigerant loading and incorrect indoor airflow due to an inadequately sized duct system followed as the most important cause of increased energy use.
The report ensures that the sizing, selection and installation of HVAC equipment in accordance with industry-recognised procedures is critical to ensuring energy efficiency.
