Framework for Environmental Analysis of Residential Heating Systems

To get a systematic assessment of a residential building heating system’s environmental performance, the impacts that occur throughout the different stages of the system’s life-cycle (raw materials acquisition and processing, construction, use, maintenance, and end-of-life) need to be identified and quantified. The environmental impacts that occur during the construction and end-of-life phases for heating systems are not well known. Once those impacts are known along with the impacts from the other building life-cycle stages, residential heating system designs could be evaluated for their environmental impacts, areas or processes of significant impact could be targeted for improvements, and alternate designs could be compared. This analysis is best performed using life cycle assessment (LCA) which identifies each component of a system (all resource input streams and potential emission or waste sources), and applies mass-balance calculations (where inputs equal outputs) to them. This paper focuses on an LCA framework for analysis of residential heating systems. The choice of study boundary, activity selection and detail, and direct vs. supply chain impacts are addressed. Process diagrams showing environmental impacts for the construction and end-of-life phases of gas-forced air and solar radiant floor heating systems are presented