A recent study from the US NIST (National Institute of Standards and Technology) Sensitivity analysis of installation faults on heat pump performance, quantifying efficiency losses due to common installation errors, has concluded that improper installation could increase household energy use for space heating and cooling by the order of 30 percent over what it should be.
Benefits of improved energy efficiency ratings could be lost if the equipment is not installed properly. 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 causes of increased energy use. The study emphasizes that sizing, selecting, and installing HVAC equipment according to industry-recognized procedures is critical to ensuring expected energy efficiency.
Source: NIST – Engineering Laboratory