Variability of optimal solutions for building components based on comprehensive life cycle cost analysis

•Developed a complete framework of building life cycle cost assessment.•Optimized building components to minimize life cycle cost.•Operational energy and initial cost are major contributors to life cycle cost.•Two financial scenarios are discussed: constant and dynamic energy prices.•Optimal component combinations vary with different lengths of building's life span.

Building energy contributes to a significant fraction of the total energy cost during all processes of its life span. Buildings are dynamic, non-linear systems with a large number of components that strongly influence total building energy consumption. Therefore, it is challenging to find an optimal combination of building components to minimize the building life cycle cost (LCC). This paper proposes a framework of building systems optimization designed to minimize life cycle cost by combining optimization algorithms and a comprehensive building life cycle cost model. A case study based on an office building demonstrates that annual energy costs and initial construction costs are major contributors to the whole building life cycle cost. A case study of an office building shows that when the building lifespan is greater than 30 years, the cumulative annual energy consumption cost is projected to be higher than the initial construction cost. Finally, optimal component combinations vary with different lengths of a building's life span. For instance, wood window frames become the optimal component for less energy and maintenance cost when the building lifespan changes from 14 to 60 years.