Electricity consumption in various types of buildings can be viewed in terms of periodic and irregular activity, or in terms of long-term trends, periodic activity and irregular activity. These different view points vary in terms of time frame, from hourly to seasonal, making it difficult for construction models to accurately predict electricity consumption. A polynomial-Fourier series (P-FS) model is developed to analyze period activity and long-term consumption trends for use by middle management and engineers. Case studies show that the P-FS model provides accurate predictions of electricity consumption, which is very useful for evaluating energy policy and determining forward-looking electricity budgets based on limited data inputs and mathematical iterations. (C) 2016 Elsevier B.V. All rights reserved.