About this report
This analysis is part of a series from our new report, Technology and innovation pathways for zero-carbon-ready buildings by 2030, and provides the strategic vision of experts from the IEA Technology Collaboration Programmes (TCPs) on how to help achieve some of the most impactful short-term milestones for the buildings sector outlined in the IEA’s Net Zero by 2050 Roadmap; each report’s title reflects one of these milestones. Learn more about the report and explore the TCPs.
A key benchmark for the building stock to meet net zero emissions goals is the implementation of mandatory zero-carbon-ready1 codes for the residential and commercial sectors by 2030. Just 5% of new buildings were zero-carbon-ready in 2020, and an array of advanced technologies, regulations and policies are needed to reach the 100% target by 2030. Building energy codes2 currently provide the most effective way to improve energy performance, and are particularly critical as buildings typically remain in operation for many decades, if not centuries, and turn over slowly.
To meet the requirements of a net zero world, building energy codes are increasingly complemented by other governmental regulations, including using carbon-based metrics, incorporating technologies such as PV (photovoltaic), EV charging infrastructure and installation of grid-interactive appliances and equipment. In fact, building energy codes (especially aggressive ones) are most effective and cost-efficient if part of a thorough package of supporting policy interventions promoting ultra-high-performance buildings. The IEA Energy in Buildings and Communities (EBC) TCPs have examined zero-carbon-ready codes and other forward-looking approaches largely based on experiences with “traditional” building energy codes for new construction.
In the IEA’s Net Zero by 2050: A Roadmap for the Global Energy Sector, mandatory zero-carbon-ready building energy codes are in place globally by 2030, for both new buildings and the retrofit of existing buildings. Typically, it takes at least several years for jurisdictions to analyse, develop and adopt new building energy carbon codes, plus additional years for them to take effect and be implemented by builders. Given the long lead times needed, it is critical to develop new codes as soon as possible.
Building energy codes have been a central tool for many countries for half a century to increase the energy performance of newly constructed buildings. Codes are increasingly expanding their remit from new construction to existing buildings, either requiring certain minimum energy efficiency measures at times of major renovations or establishing deadlines for efficiency performance upgrades in the absence of retrofitting to increase building energy performance. There are numerous supporting instruments that are being considered and adopted around the globe; these include performance labelling, certificates, mandatory energy and/or carbon disclosure programmes at the point of sale, tax inducements and/or utility-based incentives, training for builders, among other initiatives. Strong building codes also improve occupants’ health, comfort and productivity, as well as increase climate resilience and mitigate energy price hikes.
Different components of building envelopes and energy producing/consuming systems (e.g. heating, ventilation and air conditioning) that are integrated in the structures, may have their own minimum efficiency performance standards. In many countries there is also an alternative compliance option (or path) that, rather than prescribe minimum individual measures (e.g. insulation), instead sets minimum building energy performance-based standards, regardless of the technology options chosen to achieve that (simulated) performance.
Developing and implementing new standards and energy codes is a very challenging, complex process. That is in part because nearly all buildings are designed and constructed one-by-one, with energy codes differing – due to a host of market, climate and regulatory reasons – by country, regions, states, and even local governments. Additionally, as is so often the case with energy efficiency, there are many stakeholders and industries involved in the decision-making process, from producers of materials, utilities, architecture and engineering companies, construction firms and subcontractors, building owners and occupants, among a multitude of many others; this fragments both the benefits and the costs of building energy codes.
Creating new energy regulations and standards as zero-carbon-ready codes gather pace will require significant, aggressive coordination among multiple groups. Industries and government policy makers need to ensure a fair balance for regulating the allocation of buildings emissions to the different stakeholders of the construction process to ensure new codes are ready by 2030.
According to the IEA’s latest tracking report for Building Envelopes, about 80 countries have mandatory or voluntary codes in place. This represents an increase of 30% in countries with energy codes since the Paris Agreement in 2015, which accelerated previous adoption trends. Efficiency improvements and energy codes in buildings are the second most frequently cited strategy in the Nationally Determined Contributions submitted by countries.
Due to the changing technology landscape, many countries have established building performance regulations that lower energy use intensity and target the use of lower carbon sources of energy. Most countries that have energy codes in place are also updating them to expand their coverage and increase their stringency to include advanced technologies and construction plans in a bid to move standard building practices closer to carbon neutrality. A few early examples include the 2022 Zero Code for California and Massachusetts Energy Zero (E-Z) Code in the United States, the C40 Net Zero Carbon Buildings Declaration, and the World Green Building Council’s Net Zero Carbon Buildings Commitments. Several countries have federal systems in which code adoption (energy and others) is done at the state/provincial level, although they typically do so upon consideration of a national model energy code.
There are two common approaches to designing building energy codes: the more prevalent “prescriptive” strategy and alternatively a “performance-based” option. Prescriptive codes typically set minimum specifications on a component-by-component basis; they are often preferred by builders, designers and other practitioners because they provide direct, explicit requirements which can be demonstrated in a relatively straightforward manner. However, prescriptive codes are not inherently flexible, and do not allow trade-offs between, say, more insulation to allow for more windows. As a result, many countries are adding performance-based compliance options for a growing number of building types, allowing the market to achieve high efficiency with the method that works best in a given case. Performance codes typically rely on whole-building energy modelling, set a maximum level of energy consumption or intensity for the building, and allow for greater use of trade-offs among measures. However, performance codes do demand more sophistication by practitioners as they factor in complex interactions among the various building components, assessed by software.
Performance codes may still (and often do) incorporate mandatory or prescriptive elements, ensuring minimum levels of performance for individual components, and may also help mitigate potential issues related to health, moisture protection and durability. Additionally, hybrid options allow trade-offs within a given system, like envelope; or that allows designers to choose from a large number of design options of pre-simulated buildings housed in specialised databases.
Because these performance options provide more design freedom, they can lead to innovative approaches that can support zero-carbon-ready codes. Performance codes become even more complex – and valuable – as additional considerations, in particular CO2 emissions, are included.
In addition, more jurisdictions are implementing “stretch” codes. These are generally alternative codes or compliance pathways which are more stringent than the base code. In some cases, these codes are incentivised through utility programmes, can be activated as compulsory through local ratification or carry the expectation that they will become mandatory in the future. For example, the US Massachusetts Stretch Code establishes advanced requirements, and local jurisdictions may choose to opt-in at any time. The British Columbia (Canada) Step Code establishes a series of incremental improvements, targeting net zero energy readiness by 2032. One of the key benefits of the stretch approach is that it provides adopting jurisdictions, as well as design and construction professionals, with insight on regulatory requirements into the foreseeable future, helping industry prepare for, and adapt to, significant market changes. Stretch codes allow jurisdictions to test new provisions, make incremental corrections or improvements, and develop technical assistance resources to implement them (e.g. compliance tools or training programmes) before they are fully incorporated into law. Stretch codes also allow a sub-jurisdiction to adopt stronger building codes than their “parent” jurisdiction does, due to market, climate or political factors.
Building energy codes by jurisdiction, 2019-2020