Secondary Author(s)

Parker, Danny; Shirey III, Don B.

Report Number




HVAC; Buildings


Previous studies have shown that residential air-conditioning system oversizing is a common practice that has both energy and comfort penalties. A Florida Power and Light / Florida Solar Energy Center (FSEC) study involving over 350 homes found that 50% of the studies AC systems were over sized by 120% or more (James et al. 1997). The same study found oversizing AC systems by 1.0 to 1.2 times Manual J resulted in 3.7% higher cooling energy use and oversizing systems 1.2 to 1.5 times Manual J resulted in 9.3% higher cooling energy use.

The goal of Task 3.2, Benefits of Proper Sizing, was to demonstrate the benefits of proper air conditioner sizing to contractors, customers and utilities. Field tests were conducted in case study homes; four homes were tested in Florida by FSEC and additional homes were tested in Wisconsin by the Energy Center of Wisconsin (ECW). The Wisconsin tests will be reported separately.

Date Published


Local Subjects

Buildings - HVAC


FSEC Energy Research Center® Collection



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In Copyright