July 7, 2022 Jeff Rosenblum
Over the past few years, the government has mandated increased minimum efficiencies for about everything, including heating and air conditioning equipment.
While, in many ways this is good for the consumer, it has also created comfort problems due to the necessary changes in equipment design. To attain these higher efficiencies, both the evaporator and condenser coil sizes have had to be substantially increased. This has caused problems in locating the condensing units due to the increased sizes. The evaporator coils have had to increase, not only in physical size, but also in the number of fins per inch to have the needed surface area.
This increase in fins per inch has created increased static pressure drop across the coil. Since furnaces are designed for a total external static pressure of 0.5” water column, this increase can substantially reduce the amount of air that the blower can move, thus reducing comfort for the homeowner.
These changes are dictating that technicians better understand, and measure, system air flow in order to take advantage of the cost savings of higher efficient units. The entire SYSTEM must be properly designed to receive the benefits of a newer higher efficiency system.