Buildings have a large impact on the environment consuming 40% of U.S. energy and 70% of U.S. electricity in 2015. Buildings are complex systems,yet architecture, engineering, and construction (AEC) professionals often perform their work lacking a formal post-occupancy feedback process thatinforms the efficacy of goals for building performance and the anticipated user (occupant) experience. The aim of this paper is to contribute to closing thepost-occupancy performance knowledge gap hindering AEC professionals today to make achievable design decisions. Historically, buildings have beenenclosure and service system dominated in the context of energy consumption. Aggressive, top-down enclosure and service system requirements throughbuilding energy codes and federal efficiency mandates are quickly shifting loads in residential buildings away from traditional loads toward individualappliance loads such as water heating and miscellaneous electric loads (MELS). This study utilizes two descriptive and exploratory case studies locatedin a mixed-humid climate to evaluate 1) simulated versus measured performance of inverter-driven heat pumps in low-load residential buildings and 2)the impact of actual weather versus simulated standard climate on year-to-year energy consumption. Data is collected from two, all electric, low-load,affordable housing developments that have senior residents as their primary occupants. Data include simulated and multi-year energy use data as well asbuilding technology data. Preliminary findings suggest that a) heating and cooling are secondary loads to water heating and MELs and b) weather doesnot have a statistically significant impact on year-to-year energy use data within the investigated samples of these case studies.