Green Residential Building Tools and Efficiency Metrics

Residential buildings have the function of providing shelter, comfort, and a host of other amenities to their occupants, yet they are responsible for a large share of global negative environmental impacts. Understanding the need to reduce the negative impacts of buildings has led to an increase in both the quantity and popularity of green building rating schemes in recent years. Within most green building schemes, the common goal generally consists of an attempt at increasing aspects of the efficiency of resource use or environmental damage. Impact quantification is often reduced to modeled operational energy consumption, while the actual function is less simple to define or assess quantitatively. In many green building schemes, consideration of function is basically omitted from the assessment, except for the inclusion of a simple proxy metric. The dominant “function” metric that has emerged is floor area, carried over from commercial building assessments. Not only is floor area not a useful proxy for function provided by residential buildings, but placing it in the denominator of an eco-intensity metric results in a perverse ratio of two impacts. All else equal, increasing floor area gives the impression of increased efficiency, while masking the increased embodied and use-phase energy, GHG emissions, and materials use. This paper provides a review and initial inquiry into environmental assessment of residential buildings, addressing the utility of common metrics.