30 years, the built environment in the United States is expected to increase by an amount roughly equal
to 70 percent of today's existing building stock.
At the same time, the explosion of new energy services
in buildings is expected to continue. Absent significant increases in building energy efficiency or on site
low GHG energy production, the building sector is likely to continue to be a major contributor to GHG
emissions. Reductions in the life cycle emissions of building materials and in building sector related
transportation are also needed.
Today and well into the future, many opportunities exist for further curtailing GHG emissions
from the U.S. building sector. For example, current homes, stores, offices, and factory buildings rarely
incorporate the full complement of cost effective, energy efficient technologies and design strategies to
maximize the use of recycled building products and minimize construction waste. Renewable energy
sources account for only a small (but growing) fraction of the energy used on site by buildings.
addition, the sprawling urban landscape has spawned the need for ever longer commutes to work,
shopping, and services, with associated energy use and GHG penalties. Consideration of life cycle issues
surrounding energy use, building materials, waste streams, and sprawl suggest the need for an integrated
approach to GHG reductions. Thus, this report draws heavily on the green buildings and sustainable
Some of the opportunities for creating a climate friendlier built environment require greater
societal investment and costs. But others, particularly those focused on increased energy efficiency, could
yield net savings by lowering energy bills, reducing operating and maintenance costs, and enhancing
worker productivity and occupant comfort. Similarly, managing sprawl to reduce vehicle miles traveled
(VMT) and GHG emissions could yield significant co benefits of reduced pollution, congestion, utility
infrastructures, and lanes of highway construction.
This report describes the short term (by 2015) and long term (by 2050) potential for reducing
GHG emissions from the U.S. building sector. The report analyzes technology and policy options for GHG
reductions that take into account the competing goals, market imperfections, multiple actors, and specific
characteristics of this sector. Section 2 describes the nature and sources of GHG emissions from the
building sector, the way energy is used in buildings, the role of new construction compared with renova
Towards a Climate Friendly