Ultra Low Energy Retrofits Meet Aggressive Targets
Photo via iStock.com.
The United States is seeing a promising upward trend in ultra-low energy (ULE) buildings. While much of this progress has occurred with new construction, it is beginning to spread to existing buildings. Over the past decade, a small number of ULE building retrofit projects have been documented in more than 20 states.
In a recent blog post, Jennifer Thorne Amann, buildings program director for the American Council for an Energy Efficient Economy, reviewed some of the organizations findings in ultra low energy retrofits for existing buildings.
This is great news, because a highly efficient building stock is one of the cornerstones of a prosperous clean energy economy. Today’s buildings consume roughly 40% of all energy used in the United States, and retrofits of existing buildings can produce sizable energy savings. To qualify as ULE, homes typically need to reduce energy intensity by 70-85%, while commercial buildings must do so by 60-70%.
In a new white paper, the ACEE explored retrofit progress in ULE buildings, which includes zero-energy homes and commercial buildings. "
We highlight initiatives and policies that are laying the groundwork for advanced retrofits that yield deeper energy savings. Some of these efforts demonstrate technical approaches for slashing energy use, establish technical guidance and energy intensity targets for ULE buildings, and certify post-retrofit energy use. Others aim to deliver deep retrofits at a larger scale," Amann said.
These initiatives were developed and operate largely outside the realm of utilities and other traditional energy efficiency program administrators.
In the white paper, Amman wrote that dozens of existing homes and buildings are operating at ULE levels, including a growing number of zero energy buidilngs that produce as much energy as they consume.
"We are beginning to see home and building retrofits that yield energy efficiency improvements of 50–90%, the levels needed to achieve zero-energy performance with the addition of renewables. This level of savings goes far beyond the 15–30% savings resulting from typical retrofit projects," she said.
Many, such as Passive House Institute US’s PHIUS+ certification, can serve as the technical basis for programs looking to expand deep retrofit activities and program investments. Others are pilots that could be adopted by programs, such as Vermont’s Zero Energy Now, which is now a part of Efficiency Vermont’s program portfolio.
Retrofit activity in both the residential and commercial sectors lags far behind the market potential and the level needed to meet increasingly aggressive energy savings and environmental goals. Comprehensive retrofits of homes and buildings as an important measure in efforts to halve US energy use in 2050 relative to baseline projections for that year. By 2040, retrofits could contribute 11% toward that goal under the assumption that 50% of homes and 75% of commercial floor space are retrofit with an average savings of 30%. In the residential sector, roughly 2% of the existing housing stock must be retrofit each year to meet this goal—for each year this number is missed, therate must be higher in future years or savings must ramp up beyond 30%.
Current retrofit rates fall far short of these levels. Since 2002, less than 1% of existing single family homes have been retrofit through comprehensive home retrofit programs. If we add in the roughly two million homes that have been weatherized through the federal Weatherization Assistance Program since 2000, the total is still less than 3.5% of the stock. In the commercial sector, an estimated 2.2% of floor space, or 2 billion sq. ft., are retrofit each year, with median energy savings of roughly 11% per building relative to average building energy use intensity. "If we are serious about energy savings goals, both the scale and scope of retrofit activity must be accelerated far beyond current levels," Amman wrote.
Given the scale of the challenge, we will need a comprehensive set of complementary policies, programs, and initiatives, along with strategic research, to achieve a high level of ULE building performance in our existing building stock. Experience from these groundbreaking initiatives, coupled with broader lessons from building retrofit markets, provides useful insights into policy and program activity. Recommendations from the paper include the following:
- Set aggressive energy savings targets at the policy, program, and project levels to create a strong impetus for action
- Leverage existing policies and programs to take advantage of existing infrastructure and relationships
- Establish the right requirements and carefully designed policy mandates and program rules to improve project outcomes and scale up ULEB retrofit activity
- Meet customers where they are through flexible program offerings that address their needs and interests
- Call on the community to help build broader and deeper commitment to retrofits
- Engage occupants to ensure better retrofit outcomes and building energy performance
- Do the research needed to expand available solutions for more building types
"By building on these recommendations, we can drive greater demand for ULE retrofits, as well as the mechanisms for delivering them," Amann said.
Read more about sustainability trends.