An evaluation framework for exterior envelope wall systems for the homebuilding industry

Homes built using innovative exterior envelope wall systems feature improved energy efficiency, maintainability, interior comfort, and fire safety when compared to homes built using the currently widespread platform framing system. However, a significant disconnection exists between the benefits of these innovative wall systems and their use in the homebuilding industry in the United States. This study developed an evaluation framework for exterior envelope wall systems. The proposed framework is based on methodologies often suggested in literature as holding promise for contributing to increased demand and adoption of building systems. Multiattribute decision analysis (MADA) and utility theory as well as artificial intelligence tools are applied in the framework as follows: (1) a set of attributes that characterizes wall systems is identified for the framework, (2) analytical hierarchy process (AHP) is used to determine the relative weights of the attributes, (3) a neural network is utilized to aid in the prediction of thermal performance (one of the attributes), (4) Likert scales and models specifically developed for the evaluation framework are utilized to score the performances of the wall systems on the various other attributes, (5) utility theory is utilized to normalize the attribute performance scores under consideration of decision-maker value systems, and (6) the resulting attribute utilities are aggregated using an additive weighted utility model. The framework, which is divided into a part for homebuyer evaluations and a part for homebuilder evaluations, proves to be usable to demonstrate relative advantages/disadvantages of exterior envelope wall systems. A case study further demonstrates that there is no linear relationship between performance and decision-maker satisfaction. This fact, although intuitive, clearly demonstrates the usefulness of using utility theory, in addition to attribute weighing, as a means of capturing decision-maker value systems and producing meaningful evaluation results.