PurposeArguments for the design of sustainable university buildings have emerged in South Africa. Energy being a major determinant of the sustainability of buildings, the purpose of this study was to examine the influence of various building and indoor environmental parameters on the energy performance of university buildings in South Africa.Design/methodology/approachA quantitative survey research method, administered within the context of university buildings in South Africa, was used. Data about 16 buildings from three universities were collected. Relevant, inferential statistical analyses were conducted to examine the relative influence of the building parameters on the energy consumed in the buildings. Also, regression models within building parameters were developed independently and in a combination that could be used to estimate energy consumption in the university buildings.FindingsFindings suggested that building and indoor environmental parameters of humidity, indoor temperature, volume, illumination, and window width ratio (WWR), in that order, influenced energy consumption significantly, and also, had direct empirical relationships.Practical implicationsOptimising the building and indoor environmental parameters in design will enhance energy-efficiency in university buildings in South Africa.Originality/valueThis study contributes to the literature in terms of understanding the order of influence of building parameters on energy consumption in university buildings in the temperate climatic zone of South Africa. It also established empirical models between building and indoor environmental parameters and energy consumption, both independently and in combination, that could assist in designing energy-efficient and sustainable university buildings.