Volume 3, Issue 9 (October 2006)
Comparison of the Life Cycle Assessments of an Insulating Concrete Form House and a Wood Frame House
An environmental life cycle assessment (LCA) was conducted on a single-family house modeled with two types of exterior walls: wood framed and insulating concrete form (ICF). The LCA was carried out in accordance with the guidelines of the ISO 14000 family of standards. The LCA includes the inputs and outputs of energy and materials from (i) extraction and manufacturing of materials, (ii) construction, (iii) occupancy (including heating and cooling energy use), and (iv) maintenance over a 100-year life. The houses were modeled in five cities representing a range of U.S. climates: Miami, Phoenix, Seattle, Washington, and Chicago. The results show that in almost all cases, for a given climate, the environmental impact in each category is greater (worse) for the wood house than for the ICF house. The reduction in environmental impacts provided by the ICF house compared to the wood-frame house varied from 3% to 6%, depending on climate. Furthermore, the most significant environmental impacts are not from construction products but from the production and household use of electricity and natural gas. Since the ICF walls are more highly insulating and energy efficient than the wood-frame walls, the ICF house has lower impacts. Among construction products used in the house, wood products and copper tubing have the largest environmental load, followed by cement-based products.