What factor can affect the energy efficiency of HVAC installations significantly?

The size and placement of ductwork play a crucial role in the energy efficiency of HVAC installations. Properly sized ductwork ensures that air moves smoothly through the system without excessive resistance or loss of airflow. If the ducts are too small, they can create a bottleneck, leading to increased energy consumption as the system works harder to maintain the desired temperature. Conversely, if the ducts are too large, they may result in inadequate airflow and ineffective heating or cooling.

Additionally, the placement of ductwork is essential. Ducts should be situated in conditioned spaces whenever possible to minimize heat loss or gain. Ducts running through unconditioned spaces, such as attics or crawl spaces, can significantly impact the efficiency due to thermal losses. Correct installation reduces the likelihood of air leaks and ensures that the system operates at its intended performance level.

The other factors, such as the type of refrigerant, location of the condensate pan, and temperature setting of the thermostat, may influence efficiency to some extent, but they generally do not have as direct or significant an impact on the system's overall energy use compared to the size and placement of ductwork.