Building form does influence energy consumption. Designing low-energy architecture to minimize energy consumption requires thoughtful articulation of the shape and form of a building. The Architect's decision-making for more energy efficient building form is often based on rules of thumb. Historically, the rule of thumb regarding passive solar building design suggests that form and orientation matter to overall energy performance. The question of how much impact does form have varies between project to project, due to climate, location, and building size. However, evaluation of energy performance specifically relating to building form is difficult to quantify because of the large solution space, but nonetheless important to understand. The paper presents a methodology to evaluate building form to in order to compare energy consumption of geometric variations and material considerations through two types of sensitivity analyses. First, a review of related studies discussing energy and form are discussed, second the geometric methodology for vertical and horizontal proportion is described, and finally the linear screening local sensitivity index and a Morris global sensitivity results are reviewed. Findings compare geometric and material sensitivity, as well as the two different types of sensitivity analyses. Results indicate that both the vertical and horizontal geometric proportion is equally as sensitive as certain material aspects related to building energy use. Outcomes provide building designers clarity on the formal variations in the early design phase informing design decision-making. (C) 2014 Elsevier Ltd. All rights reserved.