The rapid deployment in the building sector of clean energy technologies and behavioural shifts, supported by innovation strategies, has the potential to significantly reduce carbon dioxide (CO₂) emissions by 2030 and paves the way to achieve the zero-carbon buildings stock targets under the IEA’s Net Zero Emissions by 2050 Scenario (NZE Scenario). Buildings operations account directly and indirectly for approximately 30% of global energy sector emissions.

The IEA projects the global building floor area to grow by 75% in the next 30 years, with around 80% of the increase in emerging markets and developing economies. Despite the substantial corresponding increase in energy demand by mid-century, total direct emissions from the building sector need to contract sharply, falling from about 3 Gt in 2020 to less than 2 Gt in 2030, and to just 120 Mt in 2050, according to the NZE Scenario. Meanwhile, indirect emissions also need to go to zero by decarbonising power generation and district heating.

Reaching those targets for a zero-carbon buildings stock by 2050 is a significant challenge, but one that also opens important opportunities. The current decade is a critical period for governments to put in place policy frameworks and regulations to support this vision. Behavioural changes play an essential, complementary role in reaching decarbonisation targets. In the residential building sector, a roughly 10% reduction in the cooling and heating of homes could potentially be achieved by 2030 through behavioural changes. Decarbonising both existing and new buildings will also require a range of measures that often need to be tailored to local climate conditions, occupant behaviour and technology availability.

A key milestone in transforming the global building sector in the NZE Scenario calls for all new and retrofitted buildings to be at zero-carbon-ready levels by 20301. This requires buildings to comply with criteria on energy efficiency, low-emission fuel use, life cycle-based CO₂ emissions reporting, integration with electricity systems relying on high shares of variable renewables and resilience to changing climate conditions.

Just 5% of new buildings construction was zero-carbon-ready in 2020, with a multitude of actions, regulations and policies needed to reach the 100% target by 2030. Retrofitting existing buildings is particularly challenging given the long lifespan of structures. In fact, approximately two-thirds of the global building floor area that exists today will still be in use in 2040. By 2030, the goal is to have retrofitted 20% of the existing building stock to the zero-carbon-ready level, increasing renovation rates to at least 2% by 2030 compared to less than 1% now.

Latest data shows that about 80 countries have mandatory or voluntary energy building codes in place, and many are updating them to reflect the continuous evolution of standards in construction practices, materials and technologies. Nonetheless, there are only around 45 with mandatory codes covering the entire buildings sector and just one-third of the global floor area additions to 2030 will be in countries with such codes.

Despite additional progress on energy efficiency and the decarbonisation of electricity generation, these measures so far are not enough to curb the growth in CO₂ emissions from buildings operations, which increased by about 1% per year on average over the last decade.

One exception was 2020, when direct and indirect CO₂ emissions in buildings operations plummeted to about 9 Gt, primarily because of the negative effect of Covid-19 pandemic restrictions on commercial activity. This decrease, however, was temporary as 2021 global CO₂ emissions from the buildings sector rebounded back above 2019 levels as lockdowns were lifted.

At the same time, Russia’s invasion of Ukraine has led to severe supply disruptions and a surge in prices for oil and natural gas, along with many other commodities. The current global energy crisis has led to record-level prices for household consumers and for businesses across entire supply chains, adding even more urgency to accelerate the clean energy transition for both residential and commercial buildings.

Technologies that are available on the market today are theoretically able to provide nearly all of the emissions reductions required by 2030 in the NZE Scenario, but a multitude of complex issues make full implementation very challenging at present. Key issues that need to be overcome include increased affordability and market availability of clean, flexible and efficient buildings technologies, development of effective policy frameworks and formidable behavioural changes in consumers, which is a fundamental prerequisite for the sweeping transformation of energy systems, including for the building sector.

The IEA’s landmark Net Zero by 2050: A roadmap for the global energy sector outlines more than 400 energy technology and policy milestones needed to meet the mid-century targets. In this report, experts from the IEA Technology Collaboration Programmes2 (TCPs) provide their strategic visions on how to overcome the challenges and offer recommendations for the technology solutions, innovation strategies and policy instruments needed to help deliver the required milestones for buildings by 2030 outlined in the NZE Scenario – valuable benchmarks on the road to 2050.