Evaluation Of Air Conditioning Performance Degradation: Opportunities From Diagnostic Methods

Secondary Author(s)

Parker, Danny

Report Number





Buildings; Air Conditioning


This paper reports the first ever long-term empirical measurement of the degradation of residential air conditioner/heat pump (AC/HP) performance. We describe opportunities from development of automated heuristic algorithms to identify poorly performing systems. From 2012 - 2016, FSEC monitored 56 homes in Florida as part of a retrofit project which gathered detailed HVAC end-use energy data. Many research sites had two consecutive years of heating and cooling data and some had more than three years along with interior temperature data available. Within the analysis, cooling system performance at many sites was found to worsen over the baseline period, typically degrading 5%, and ranging from -8% to 40%, per year. Some systems experienced sudden, severe declines in performance often associated with need for system replacement. Using these data, an algorithm was developed to automatically evaluate AC/HP performance against weather. These findings were empirical in a large sub-metered sample of air conditioners and heat pumps evaluated over 2-5 years.

Date Published



Presented at 2018 ACEEE Summer Study on Energy Efficiency in Buildings

Copyright © 2018 American Council for an Energy Efficient Economy

Local Subjects

Buildings - Air Conditioning


FSEC Energy Research Center® Collection



Rights Statement

In Copyright