Buildings represent a large portion of total US energy usage. Religious facilities, which consume a significant percentage of the total floorspace and energy usage in the commercial sector, have generally not been the focus of efficiency studies or building energy audits. Religious facilities are characterized by unique patterns of occupancy and energy use. This paper presents the results of a long-term, in-depth energy study of architecturally similar church buildings in different climates in an effort to identify energy efficiency opportunities in religious buildings. Specifically, the paper details the experiment design and general usage trends from the buildings in different climates. A clear relationship between energy use and climate is evident, with HVAC and lighting systems consuming the majority of energy. An analysis on the prediction capabilities of using only a small subset of sensors to achieve similar results reveals the uncertainty of results by not metering all loads. (C) 2015 Elsevier B.V. All rights reserved.