Closing the Building Decarbonization Gap

As we enter 2023, the need to align building energy codes with the path to decarbonization is increasingly pressing. As reviewed in December, the building sector is not on track. In this first blog of the new year, we review strategies that have been championed by leading jurisdictions in North America to drive building performance faster than the current trajectory of baseline code development.

In 2020, the United Nations Economic and Social Council (UNESC) published a framework guideline for energy efficiency standards in buildings to support improvements in building energy codes to support the sector’s decarbonization. In new construction, the goal is for building heating and cooling demand to be limited to 4.8 kBTU/ft2 (15 kWh/m2) annually. The target for total primary energy use intensity (EUI), including ventilation, lighting and hot water, is 14 kBTU/ft2 (45 kWh/m2). When plug loads are included, the target is 28 kBTU/ft2 (90 kWh/m2).

To put this into perspective, the primary EUI of a medium office building built to ANSI/ASHRAE/IES Standard 90.1-2019 (ASHRAE 90.1-2019) is 30 kBTU/ft2 (94 kWh/m2), according to the U.S. Department of Energy’s (DOE’s) Energy Savings Analysis. Multi-family apartments built under that standard reportedly average an EUI of 38.5 kBTU/ft2 (120 kWh/m2). Note that ASHRAE 90.1 does not regulate plug loads.

The Passive House Institute’s (PHI) target for certification matches the UNESC target with an annual heating demand of 4.8 kBTU/ft2 (15 kWh/m2). British Columbia’s Step Code’s highest performance tier has a Thermal Energy Demand Intensity (TEDI) target aligned to 4.8 kBTU/ft2 (15 KWh/m2).

At the COP27 conference at the end of 2022, representatives from the PHI, Jessica Grove-Smith; the International Code Council (ICC), Ryan Colker; and the North American Passive House Network (NAPHN), Bronwyn Barry participated in a panel presentation on how to align better building energy codes to support a decarbonized future.

Progress of the IECC

Colker, vice president of innovation at the ICC, reflected on the progress in the U.S. model codes. He highlighted the 40% improvement in EUI delivered by the International Energy Conservation Code (IECC) since 2006 and the addition of a voluntary net-zero energy appendix in the 2021 edition. He also noted that with the U.S. Inflation Reduction Act, there is $1 billion available to support the adoption of the most recent codes and zero-energy codes by states and local jurisdictions. Approximately one-third of the funds will go to implementing the 2021 IECC and two-thirds will implement zero-energy codes.

Closing the Trajectory Gap: Policymaking

Barry, board member of the NAPHN, talked about how to close the gap between code performance and the needed trajectory. She identified that it is already possible and cost-effective to achieve significantly lower energy use than baseline energy codes provide. She also reasserted that the rate of change of the U.S. model codes is not on track to meet the decarbonization targets.

She identified three regions of North America that appeared to be ahead in building energy code stringency and applying high-performance passive house standards: British Columbia, New York and Pennsylvania.

She described the analysis of the policies and code-making in these three jurisdictions, which the NAPHN carried out. These findings have been documented in a 2022 report and several common threads support the construction of high-performance buildings. Important factors include:

• Clear targets specific for the industry to reach, which are measurable and with tools connected to support outcomes;

• Available training tailored to support specific performance targets; and

• Direct financial support for projects that are stepped, competitive, and required reporting and monitoring.

In addition, all three had active volunteer practitioner communities supporting policymakers. Where needed, policymakers also removed roadblocks that were embedded in baseline codes. They also utilized a combination of policies that lie both inside and outside the building code processes to encourage the use of higher performance standards, such as:

• Zoning incentives, e.g. allowing additional height or smaller setbacks;

• Accelerated plan approvals or reviews;

• Availability of stretch codes, e.g. step codes, net zero pathways;

• Alternative code compliance pathways, e.g. Passive House Planning Package;

• Existing building performance standards, e.g. Local Law 97 in New York City;

• Training subsidies;

• Tax credits; and

• Direct subsidies

Barry also identified several keys to why these policies have been effective:

• Having tiered code adoption programs with weighted incentives directly tied to the long-term target, such as net-zero carbon; connecting voluntary standards; and baseline codes;

• Connecting different regulatory codes, such as zoning and energy; and

• Having circular feedback loops for reporting outcomes and costs.

These insights can be important to jurisdictions seeking to make transformational changes in buildings to achieve climate change targets.

Closing the Trajectory Gap: Design and Construction

Grove-Smith, managing director at the PHI, noted that even the current trajectory of the German building energy codes is insufficient to meet the needs of a renewable grid based on the UNESC’s framework targets. She conveyed three messages for closing the gap to decarbonized buildings:

• Prioritize efficiency first

Operating energy consumption is the largest contributor to emissions, which are locked in for the lifetime based on the building design. She argued that simply relying on the decarbonization of the grid is not a sufficient strategy because “the grid has both practical and physical limitations.” Meeting energy requirements with renewable energy will only be economically feasible if buildings are efficient enough. Lastly, Grove-Smith noted that energy-efficient buildings also address the social benefits of resilience, health and well-being, and reduced fuel poverty.

• Quality assurance is key

Because it addresses the performance gap between as-designed and as-built, ensuring that the designed efficiency is delivered. She identified four aspects of delivering reliable building performance:

1. People with appropriate expertise;

2. Simple and robust energy modeling;

3. Reliable energy labeling of components; and

4. A quality assurance process to verify the design.

• Voluntary standards are important

Code and policy development moves slowly, so the availability of stretch voluntary standards provides a useful tool for market transformation. When used as part of policy incentives, such standards increase the use of newer technologies and techniques. This builds market capability and expertise, which then charts the direction for baseline codes.

Grove-Smith closed by reminding us that buildings have a long life and the window for limiting climate change is closing fast: “What we build today either contributes to climate change mitigation and adaptation or creates a persistent liability, generating high emissions for decades.” Let’s choose to build better.