In the News

October 20th, 2011

Building Energy Trend: Outcome-Based Energy Codes

Key Points

• Existing building codes use predictive compliance approaches that fail to regulate actual energy use.
• An outcome-based approach includes performance targets and accountability through measurement and reporting.
• Key components include accurate usage data, metering capabilities, and adjustable reporting tools.

Buildings account for 40% of the total energy consumed in the United States, according to the U.S. Department of Energy. Increasing building energy efficiency presents a substantial opportunity to save energy and help the environment through lower emissions. Energy codes are useful tools for improving building energy performance. Existing codes focus primarily on efficient design and system installation at the time of construction or retrofit. There is no provision for demonstrating compliance through actual energy use during building operation. An outcome-based code framework currently under development will do just that.

No Finish Times

Energy codes generally provide two compliance paths—prescriptive and performance. The prescriptive approach specifies minimum requirements for individual building components and systems, while the performance method compares a proposed design against a base or reference design.

While these compliance methods help to ensure that energy-efficient features are introduced, they assume that building systems and components are installed correctly and that equipment and controls are used effectively. Efficient systems can be put in place according to code requirements, but there is no guarantee that they will be used as intended or properly controlled. The actual outcome of the building's energy use is not evaluated. Also, these compliance approaches focus on major building systems and components, while failing to take into account major energy users such as computers, office equipment, and refrigerators.

"Current energy provisions do not look at the actual performance of a building covered by code," according to David Conover, Senior Technical Adviser at the U.S. Department of Energy's Pacific Northwest National Laboratory, "they instead provide criteria for design and construction that we assume will work, but do not necessarily know." Conover uses the analogy of running a race. You can check off what the participants are wearing, what they ate, past running times and so on, give them a rating and send them home—or, you can actually run the race and take their finish times. "Energy codes today do not look at or regulate finish times," he says.

An Alternative Approach

The New Buildings Institute, in partnership with the U.S. Department of Energy's Pacific Northwest National Laboratory and other organizations, is currently developing an outcome-based energy code framework that they hope will provide a more accurate picture of building energy performance. Building owners and designers will be required to demonstrate compliance with set performance targets through measurement and mandatory reporting. Accountability will be based on actual energy performance rather than predicted energy performance.

An outcome-based approach can provide other benefits as well. The focus on energy end use will make it easier to account for variations across building types and include existing and historic buildings. Operational and occupant energy use will be addressed, increasing the accuracy of building energy-performance data. In addition, designers and building owners will have more flexibility to look beyond the often strict specifications of existing compliance paths to test out the most cost-effective energy-saving measures and explore innovative approaches.

The latest draft of the International Green Construction Code (IgCC)—currently being developed by the International Code Council—includes an outcome-based compliance path. Buildings are required to achieve an annual net energy performance and peak net energy demand based on occupancy type. Provisions for energy metering and reporting, as well as post-construction building commissioning are also included. However, this approach within the IgCC has been criticized by industry experts for failing to evaluate buildings as a whole and for lacking proper incentive or enforcement mechanisms. Final action hearings for the IgCC are scheduled for November 2011, with the final form to be approved at that time.

According to the New Buildings Institute, a number of key components must be put in place to integrate outcome-based compliance within the current code structure:

• Better data about actual building energy use, so that realistic performance targets can be set
• Adjustable tools and methodologies for consistent reporting of building performance information
• Incentive and enforcement mechanisms that apply after the building has been occupied and operational for at least one year
• Metering capabilities integrated into the building design to enable real-time performance monitoring

The switch to an outcome-based approach would impact not only energy codes, but utility programs, green building standards, as well as raise a host of legal questions. Tenants, owners, builders, developers, and policy-makers would all be affected. In 2011, advocates of an outcome-based approach hope to publish a Roadmap to Outcome-Based Policies. Through this document, according to Jim Edelson, Senior Project Manager with the New Buildings Institute, they hope to "bring together this wide range of affected parties, and begin a whole new level of interaction."

Adopting an outcome-based approach should help to improve building energy performance and increase flexibility in existing building upgrades, but the process will take time. "It can be done now for government buildings," according to Conover, "for the private sector it may take a few years to create the infrastructure to support such codes."

References

New Buildings Institute. Outcome-Based Code Summary. 2010.

U.S. Department of Energy. Buildings Energy Data Book. 2010.

Source: Questline.com http://members.questline.com/Article.aspx?articleID=19145&accountID=1&nl=11464