Improvements in the International Energy Conservation Code (IECC)—driven by a combination of federal mandates and superior construction methods pioneered by voluntary green-building rating systems such as the Department of Energy’s Build America Program, the Environmental Protection Agency’s Energy Star, and private efforts such as LEED—have already paved the way toward dramatic improvements in the energy profile of new housing. So, by 2020, most of the United States will be building under the upcoming 2015 and 2018 energy codes.
Unfortunately, however, new housing represents only a fraction of the U.S. housing stock. We currently build about 500,000 new units annually, and the superior energy efficiency of these homes offset the 130 million units of existing housing that are an average of 34 years old, according the American Housing Survey of the U.S. Department of Commerce. This is why, despite all of the energy efficiency advances made in new-home construction, the total amount of energy consumed by the sector has remained flat.
This is not necessarily bad news. Total U.S. energy consumption in homes has remained relatively stable for many years precisely because the energy efficiency of new homes has offset the increase in the number and average size of housing units, according to data from the Residential Energy Consumption Survey. This data shows a downward trend in average residential energy consumption over the last 30 years despite increases in the number and the average size of homes, as well as an increased use of electronics. Nevertheless, this improvement does not get us to the 60 percent overall reduction in energy consumption envisioned in the 2030 Challenge, which sets goals for existing buildings as well as new.
The 2030 Challenge goals assert that:
- All new buildings, developments, and major renovations shall be designed to meet a fossil fuel, greenhouse-gas-emitting (GHG-emitting), energy consumption performance standard of 60 percent below the regional (or country) average/median for that building type.
- At a minimum, an equal amount of existing building area shall be renovated annually to meet a fossil fuel, GHG-emitting, energy consumption performance standard of 60 percent of the regional (or country) average for that building type.
While the focus on advancing green codes and rating systems for new homes has made astonishing progress--and has proven to the industry how much better we can build--the focus on improving the existing housing stock seems to have lost steam.
In the residential arena, when HOME STAR legislation fell under political pressure, the national weatherization effort stalled. The legislation was designed to create jobs in existing industries by providing strong short-term incentives for energy-efficiency improvements in residential buildings. Typically, homeowners have only financial incentives to perform energy upgrades, and these were provided largely through government and utility incentives that have been reduced or eliminated.
Some code provisions promise to have a direct, if unheralded, effect on existing housing. One of the most important updates came with the 2009 International Building Code (IBC), chapter 419, which attempted to address live-work in a prescriptive manner. The integration of live-work into the IBC allows builders and developers to actually build zero-commute housing, rather than just advocate for it.
Continued progress in green codes and rating systems for new construction is by no means assured. In 2012, we have seen serious pushback on Energy Star v.3, movement in several states to slow the adoption of new model codes from three to five year cycles, and, most recently, strong opposition to LEED version 4 (LEED v4). If this sort of industry and political repositioning continues, as it is likely to, the optimistic predictions we’ve made beyond 2012 may not materialize. However, we can still make significant progress with strong construction industry support by focusing more intently on developing aggressive goals for greening our huge stock of existing houses.
Doing this will require engaging the remodeling community more vigorously through the DOE’s Build America and the EPA’s Energy Star programs. Rating systems like California’s Build It Green, GreenPoint Rated Existing Home certification exist because utility companies such as PG&E realize the benefit of high-performance retrofits. On a national basis, the U.S. Green Building Council should further develop LEED credits for remodeling. The LEED for Homes rating system currently includes gut rehabs, but not other remodeling projects that encompass less than the entire structure. The NAHB Model Green Home Building Guidelines score major remodeling projects. The association would be a strong advocate for focusing on remodeling and rehabilitation since here low hanging fruit remains, and the activity would bolster the beleaguered housing industry.
To wit, the ANSI National Green Building Standard (NAHB Green) offers the most robust certification path to date for a single-family home or multi-unit building remodeling project. But as more jurisdictions throughout the U.S. adopt the 2012 International Green Construction Code and future updates, high-performance remodeling of residential and commercial structures should become easier through prescriptive guidelines and should gain market legitimacy through the municipal blessing of adopted codes.