Commercial building indoor environmental quality models: A critical review

Indoor environmental quality (IEQ) models merge various influencing IEQ factors into a single overall indicator. The outcome of the IEQ model is usually a numerical rating or score that provides an evaluative summary of the IEQ performance. Many publications have developed IEQ models from their field measurement and/or satisfaction survey results, however with distinct measurement protocols, IEQ weighting schemes and analytical methods. This paper presents a comprehensive review of 25 studies focusing on developing IEQ evaluation models in commercial buildings. Two IEQ measurement approaches (objective and subjective measurement), and three types of IEQ models—subjective-objective models, objective models and subjective models—are first differentiated. Five commonly used analytical methods (linear regression, non-linear regression, analytical hierarchy process, ensemble averaging method, and updated IEQ acceptance model) are discussed. The interaction effects between IEQ factors and relative contribution of them to the overall IEQ satisfaction are also assessed. Twenty-five studies are then mapped by data collection method, analytical method and number of survey responses. Five key criteria for developing quality IEQ models—number of IEQ factors included, spatial and temporal variability in physical measurement, analytical methods for model development, and the number of responses if subjective surveys are carried out—are proposed and discussed. A simple ranking and scoring system is propounded for evaluating the quality of the IEQ models developed in the reviewed studies. Results show that two studies achieved a total score equal to or higher than 80% of the total score, and 16 studies achieved a minimum of 60% of the total score. This tool can help researchers quickly assess the accuracy and reliability of IEQ models developed from diverse methods and make an informed decision.