Waste Prevention and Reuse
Key findings from the Phase 2 Study
- Of the 30 different material reduction and reuse practices
evaluated, reducing home size and multi-family living achieved the
largest greenhouse gas reductions along with significant reductions
in other impact categories.
- Reducing home size by 50 percent results in a projected 36
percent reduction in lifecycle greenhouse gas emissions.
- Reducing home size is a significant leverage point for
environmental impact reduction and may be a more effective measure
than achieving minimum levels of “green” certification.
- Various sizes of multi-family housing show significant lifecycle
reductions in greenhouse gases and most other pollutants.
- Families who choose or require more living space than a “small”
home may lessen a large home’s impact by adding green building
practices and increasing the home’s energy efficiency.
- New and existing homes of any size could incorporate internal
accessory dwelling units (sometimes known as “mother-in-law
apartments”) within the home as an option to increase density and
reduce the square foot/ person ratio, provide flexible living
spaces, and achieve the environmental benefits of both small and
- More than 80 percent of greenhouse gas emissions over a home’s
70-year life occur during occupancy and are attributed to
electricity and fuel consumption. Approximately 14 percent of
greenhouse gas impacts are tied to producing the original and
replacement building materials. Constructing and maintaining the
home account for about 2 percent and transportation of building
materials accounts for less than 1 percent. Oregon’s existing
material recycling and energy recovery system reduces greenhouse gas
emissions by 5 percent over the typical 70-year life of a home.
- For other types of environmental impacts, materials contribute
10 to 40 percent of life cycle impacts.
- Only a small amount – about 6 percent – of building
material-related waste generated occurs during home construction,
with about 50 percent of waste generation occurring during 70 years
of home repairs and maintenance. The remaining 44 percent of waste
generation occurs at the time of the home’s demolition.
- Material reuse significantly reduces the amount of waste
generated and material-related impacts of production but provides
limited greenhouse gas reductions over the home’s life because reuse
does not typically affect the operational energy consumption of a
home, as do other practices evaluated.