| This study investigates alternatives to either retrofit existing buildings or replace them on the basis of life cycle environmental and economic impacts over a forty-year life. Focusing on single detached dwellings, commonly performed energy efficiency retrofits and complete replacement with a new energy efficient house are compared for a typical Toronto house. The environmental impacts considered include: global warming potential, resource consumption, solid waste generated, and atmospheric and water pollution. The capital cost expenditure and annual operating costs are represented using the simple payback method and life cycle cost method. Both retrofit activities and replacement with new energy efficient construction contribute to improving the environmental performance of the built environment. Replacement options significantly reduce the impacts of atmospheric emissions affecting global warming whereas building re-use activities are more resource efficient, reducing the amount of solid waste and environmental pollutants generated. Economically, retrofits require significantly less investment capital than replacement. |
