Buildings

Decarbonize building energy use

Decarbonizing the world’s buildings

To decarbonize the world’s buildings, it will be necessary to decarbonize the energy used in buildings. To do this, we must ensure that every energy service we use in our buildings is electrified as much as possible, using the most energy-efficient appliances and equipment, and the electricity used comes from carbon-free sources. This means that while we construct buildings to be zero-carbon and optimize building energy consumption, we also need to switch heating, cooling and cooking equipment from fossil-fueled power to zero-carbon electricity to reduce emissions from energy use in buildings.

The importance of zero-carbon electricity for decarbonizing buildings

A shift of this magnitude will require a zero-carbon electricity grid. Additionally, an increase in on-site and local off-site renewables such as rooftop solar power or community wind turbines can also help guarantee carbon-free power, especially while electricity from the grid is being decarbonized.

Key technologies for decarbonizing buildings

The technologies needed to decarbonize buildings already exist and are fairly mature. For instance, energy-efficient electric heat pumps have become a key technology for decarbonizing space and water heating. Most active cooling is already achieved through electric fans, evaporative coolers and air conditioners (which are technically a type of heat pump). Reversible heat pumps can supply both heating and cooling.

However, many heat pumps and air conditioners use refrigerants that are known to contribute to global warming. It is therefore important that all newly installed heat pumps and air conditioners use alternative refrigerants to reduce their climate impact.

Other technologies appropriate for heating and cooling include district heating, district cooling and solar thermal heating for hot water. To be sustainable, both district heating and district cooling must rely on a zero-carbon thermal energy source.

The use of biomass as a fuel source is a Paris Agreement-compatible option only when its sustainability is assured and life cycle emissions are near zero. Traditional biomass is also used as a cooking fuel, especially in developing countries, but it has substantial negative effects on health and the environment. Many buildings use fossil gas stoves for cooking, which in addition to emitting climate-damaging carbon dioxide and methane when burned, can also leak methane and hazardous compounds such as benzene even when turned off. Shifting to electricity for heating and cooking — especially highly efficient induction stoves — will eliminate the harmful emissions from both of these sources.

Challenges for adoption of sustainable solutions for building heating, cooling and cooking

There are challenges in scaling up these technologies for heating, cooling and cooking, particularly in existing buildings where retrofits to improve energy efficiency often come with high upfront costs. Behavior change is also necessary, in particular for cooking, where cooking systems can be culturally important and strong preferences for certain cooking equipment exist.

Data Insights

Is the world making enough progress toward the most important outcomes?

Systems Change Lab assesses progress made toward targets across 5 outcome indicators. Click a chart to explore the data.

What factors may enable or prevent change?

Systems Change Lab identifies 7 enablers and barriers that may help spur or impede change. Click a chart to explore the data.

Progress toward targets

Systems Change Lab tracks progress made toward targets across 5 outcome indicators. outcome indicator. Explore the data and learn about key actions supporting systems change.

Share of new buildings that are zero-carbon in operation

Ensuring that all new buildings are zero-carbon in operation is the most cost-effective way to decarbonize heating, cooling and appliances. Although there is no global data on buildings that are currently zero-carbon in operation, 5% of new buildings in 2020 were zero-carbon-ready.

Ensuring that all new buildings are zero-carbon in operation is the most cost-effective way to decarbonize heating, cooling and appliances. Any new buildings that are not operationally zero-carbon will need to be retrofitted in the next two to three decades in order to meet current climate goals, which will cost substantially more than making them zero-carbon from the start.

To advance climate mitigation efforts, all new buildings must be operationally zero-carbon as soon as possible. By 2030, 100% of new buildings should be zero-carbon-ready, meaning they are highly efficient and rely on an energy source that can be decarbonized (primarily, this means electricity that comes from clean technologies).

Unfortunately, global progress remains slow. Only a handful of countries and regions have established the kind of strict building standards necessary to ensure that new buildings minimize their energy demand and supply their remaining energy demand with zero-carbon sources. However, progress is still being made, with net-zero building certifications being introduced by ten of the world’s national Green Building Councils.

There is no global data to track progress on this indicator. However, we know that in 2020, only 5% of new buildings met this definition. In the United States, the New Buildings Institute has an interactive map to search for information about zero-energy buildings, which is an example that could be implemented in other jurisdictions.

Carbon intensity of buildings operations

The average global carbon intensity of building operations has steadily decreased since 2000. However, to achieve the 2030 target, gains made from 2018 to 2022 will need to accelerate by a factor of roughly four in the coming decade.

The carbon intensity of buildings is calculated by dividing the total carbon dioxide (CO2) emitted from energy use, including electricity, by the global total floor area. This indicator differs from the energy intensity of buildings in that it reflects not just how much energy buildings use relative to their size, but also where that energy comes from and how much carbon is emitted from producing and consuming that energy.

For all buildings (which includes residential and commercial floor area), average global carbon intensity has steadily decreased since 2000 due to a combination of relatively stable emissions from buildings and increasing floor area. Despite this trend, recent declines remain well short of the required pace and have been more than offset by increases in floor area, which rose on average by 2% per year between 2010 and 2020. As a result, CO2 emissions from buildings have remained relatively level since 2010.

The carbon intensity of building operations should fall from 38 kilograms of carbon dioxide per square meter (kgCO2/m2) in 2022 to 13–16 kgCO2/m2 by 2030 and to 0–2 kgCO2/m2 by 2050. To achieve the 2030 target for carbon intensity, gains made from 2018 to 2022 would need to accelerate by a factor of roughly four.

Currently, space heating is the greatest contributor to emissions intensity from buildings, but cooling demand is quickly growing in many places as people gain new access to cooling services. Further, as temperatures rise, space cooling will likely contribute a larger share of emissions in the future.

Policies banning fossil fuel-based heating and cooking systems have successfully spurred greater electrification of building energy end uses (and simultaneously bring health benefits), but the source of electricity also needs to be decarbonized to reduce emissions. Reducing energy intensity by improving the efficiency of energy use in buildings will also be important to minimize the impact on the grid from increased electrification of end uses.

Number of installed heat pumps globally

Heat pumps are among the most highly developed and popular solutions for space heating and cooling, as well as for water heating. Currently, only 10% of heating needs are supplied by heat pumps, and this share needs to double by 2030.

Heat pumps are among the most mature, and most popular, solutions for space heating and cooling (particularly in parts of the world that need heating), as well as for water heating. Generally, heat pumps can either be air-source, which exchange warm and cool air from the outside, or ground-source, which use shallow geothermal heat.

In 2020, there were about 177 million heat pumps installed around the world, with roughly 58 million in China, 40 million in North America, and 22 million in Europe. Crucially, heat pumps are powered by electricity, and increasing the number of installations will increase the use of electricity for heating.

It is fundamental that the power system meets its decarbonization targets so electrification in the end-use sectors, a key strategy for decreasing direct emissions, supports the transition toward decarbonization and does not contribute to increased emissions.

Currently, only 10% of heating needs are supplied by heat pumps, and this share needs to double by 2030; however, heat pump sales grew by 13% globally in 2021, with the greatest uptake in cold, northern climates (with a 40% increase in sales in Europe). To achieve a 1.5 degrees C pathway, 600 million heat pumps need to be installed cumulatively worldwide by 2030 and 1,800 million units by 2050. This would require the rate of installations to increase fourfold between 2021 and 2030.

Share of new buildings with on-site renewables

Although there is no global data on new buildings with on-site renewables, requirements to install solar panels on new buildings have begun to emerge across the world. The IEA Net Zero by 2050 scenario calls for 100 million households to have rooftop solar photovoltaic by 2030.

Electricity from renewables is key to sustainably powering heating, cooling and appliances in buildings, and some technologies can also generate heat from renewable sources to supplement electric heating.

Renewable electricity generators such as solar panels can generate electricity to power heating, cooling and appliances in buildings. To supplement electricity, however, some technologies such as solar thermal heaters can also generate heat directly to help decarbonize thermal energy demand for space or water heating.

Increasing the share of buildings producing at least part of their electricity with renewable sources on-site supports progress toward zero-carbon buildings. Each new installation helps to displace fossil fuel-generated electricity and, combined with electrification, decarbonizes building energy use.

On-site renewables, combined with storage to ease the stress on grids, are important to meet the greater power demand expected as electrification levels increase. If they are installed on rooftops, they can also reduce the impact of renewable energy on land use, sparing acreage that is more suited for agriculture or other uses.

There is currently no global data available on the share of new buildings with on-site renewables, although for solar panels specifically, 25 million households used rooftop solar photovoltaic (PV) in 2022, and the IEA Net Zero by 2050 scenario’s target for 2030 sees this number rise to 100 million.

Requirements to install solar panels on new buildings have emerged in places like California, France, Switzerland and Tokyo. Google has developed an Environmental Insights Explorer to help policy development around rooftop solar by showing rooftop solar potential in cities with satellite data. In the United States, Energy Star tracks on-site renewable energy production for commercial buildings.

Share of renewables in district heating

The global share of renewables used for district heating increased from 5.2% in 2010 to 7.1% in 2021. To meet 1.5 degrees C-aligned goals, this needs to increase over 10 times faster by 2030.

District heating systems consist of a series of underground pipes and integrated heaters that provide heat to a network of buildings in a given area. In 2022, district heating provided about 9% of global heating demand for buildings and industry. However, 90% of district heating comes from fossil fuels.

Zero-carbon options for district heating systems include the direct use of renewables. For example, geothermal district heating systems have long existed in countries such as China, Iceland and the United States, while Denmark uses solar thermal energy for district heating. Powering a district heating system with electricity made from renewables can be an option as well.

The global share of renewables in district heating increased from 5.2% in 2010 to 7.1% in 2021. This is well off track to meet the goal of 17% by 2030. The share of renewables in district heating needs to increase over 10 times faster compared to the last five years to meet this goal. Ultimately, this should increase to 100% by 2050.

Enablers and barriers

We also monitor change by tracking a critical set of 7 enablers and barriers enabler or barrier that can help spur or impede change. Explore the data and learn about key actions supporting systems change.

Number of countries with zero-carbon building codes

All countries and jurisdictions should adopt mandatory building codes to achieve zero-carbon operations as soon as possible. As of 2023, 30 countries have zero-carbon building codes.

Building codes are a common regulatory instrument used in many countries. They specify health, safety and energy standards, among other criteria, for new and existing buildings. Currently, they are strongly linked with energy performance standards, but they could also be adapted to ensure the use of zero-carbon technologies.

Moving toward zero-carbon building codes requires clear, well-communicated timeframes for increasing the stringency of regulations. Additional incentives, such as tax breaks or grants, are also important to increase compliance and improve enforcement of the regulations. Building codes are particularly effective in combination with a long-term plan to reduce building emissions intensity and the involvement of stakeholders such as developers, owners and tenants.

All countries and jurisdictions should adopt mandatory building codes to achieve zero-carbon operations as soon as possible. Although many countries have building codes (and some have building codes at the municipal or city level), particularly for energy efficiency, few currently have zero-carbon building codes in place. This partially explains the slow increase in the number of zero-carbon buildings, despite the availability and maturity of many technologies needed to implement them.

As of 2023, 30 countries (Canada, China, and the countries of the European Union) have all set codes or guidelines for near-zero- or near-net-zero-energy buildings. A net-zero-energy building produces as much energy from on-site renewables as it consumes, so such initiatives could help move in the right direction toward zero-carbon buildings. However, reorienting codes to prioritize carbon dioxide emissions reductions rather than energy use reductions will more reliably deliver zero-carbon buildings.

Number of countries with a phase-out date for installation of new fossil fuel-based heating equipment

Setting specific dates for the phaseout of fossil fuel-based equipment sends clear signals to the market and supports the uptake of low-carbon and energy-efficient technologies.

Space and water heating are responsible for approximately half of building energy use globally, so the phaseout of fossil fuel-based heating equipment will play a fundamental role in decarbonizing buildings. Installing new fossil fuel-based heating equipment slows the pace of emissions reductions, even with improvements in their energy efficiency.

Setting specific dates for the phaseout of fossil fuel-based equipment sends clear signals to the market and supports the uptake of low-carbon and energy-efficient technologies. The number of countries that set phase-out dates indicates progress in the ongoing transition away from fossil fuels.

There is currently no global data monitoring the phaseout of fossil fuel-based heating. However, a partial picture at the national level can give insights into progress; in 2024, the OECD conducted a survey on buildings and climate policy in 28 countries and found that 46% of the countries surveyed had targets to phase out the use of fossil fuels for heating and cooling. In Europe, the European Heat Pump Association published a map showing the progress of fossil fuel-based heating equipment bans.

Though many jurisdictions have recently approved regulations to phase out fossil fuels for heating in new and existing buildings, only some of these actions are driven by climate change mitigation. Following the 2022 Russian invasion of Ukraine, for example, many European countries began seeking to end imports of fossil fuels from Russia. Their strategies include varying degrees of decreased fossil fuel use, including in the buildings sector.

Number of countries committing to decarbonization of buildings sector

Although there is no global database of countries committed to decarbonizing their buildings, two recent developments offer proxies to monitor progress on country commitments: the Buildings Breakthrough and the Declaration de Chaillot.

Country commitments to decarbonizing the buildings sector can give a clear direction and signal to actors across the built environment. Although there is no global database of countries committed to decarbonizing their buildings, two recent developments offer proxies to monitor progress on country commitments. The Buildings Breakthrough was announced at COP28 and committed to by 27 countries. This initiative is part of the wider Breakthrough Agenda, which provides a platform for international collaboration between national governments to help unlock action in key sectors.

The Declaration de Chaillot emerged from the Buildings and Climate Global Forum, hosted for the first time in 2024, and counts 70 governments as signatories. With its adoption, countries commit to implementing a range of regulatory, financial and governance measures across the value chain to encourage and support the transitions needed in the sector for it to decarbonize. It also establishes an Intergovernmental Council for Buildings and Climate, with the Global Alliance for Buildings and Construction coordinating it and monitoring progress toward implementation.

Share of heat pumps and air conditioners sold that use low or zero global warming potential refrigerants

The use of refrigerants with low or zero global warming potential (GWP) can minimize the impacts of heating and cooling technologies on the climate. There is currently no global data on the share of these technologies that use low-GWP refrigerants.

Both heat pumps and air conditioners put refrigerants through pressure cycles to transfer heat — from outside to inside for heating, and the opposite for cooling. Many commonly used refrigerants, if leaked, contribute to global warming by a factor of dozens, or even thousands, compared to the contributions of the same amount of carbon dioxide (CO2). Cooling needs will also become especially important as climate change causes higher average temperatures. The number of air conditioners in households tripled from 2000 to 2022, driving increased energy use despite efficiency improvements.

The use of refrigerants with low or zero global warming potential (GWP) can minimize the impacts of these devices on the climate. The share of heat pumps or air conditioners sold with low-GWP refrigerants indicates if the best available technology is being used to decarbonize buildings.

There is currently no global data available on the share of air conditioners or heat pumps with low-GWP refrigerants. However, as of January 2024, 156 countries had ratified the Kigali Amendment to the Montreal Protocol, which pledged to phase out the most climate-damaging refrigerants. Major emitters like China and the European Union have begun embedding this commitment in law or regulations. Identifying this data will be important to ensure that the use of these low-GWP refrigerants is trackable.

Number of companies committing to zero-carbon buildings / decarbonization of own buildings

The World Green Building Council’s Net Zero Carbon Buildings Commitment pledges to eliminate net carbon dioxide emissions from new and existing buildings as fast as possible by 2030. As of July 2024, 143 companies had signed the commitment, alongside 29 cities and 6 states and regions.

Constructing new zero-carbon buildings requires innovative design choices and zero-carbon energy sources, which are often associated with higher upfront costs. Decarbonizing existing buildings similarly requires upfront costs, even though there is a positive long-term financial return —in both new and existing buildings — to decreasing total energy use and increasing energy efficiency.

Initial declarations and investments from companies can reduce costs by increasing demand, provide certainty to the construction industry and improve processes for others. In 2018, the World Green Building Council (World GBC) established the Net Zero Carbon Buildings Commitment, in which actors pledge to eliminate net carbon dioxide (CO2) emissions from new and existing buildings as fast as possible by 2030.

As of July 2024, 143 companies had signed the commitment, alongside 29 cities and 6 states and regions. The World GBC’s Commitment serves as a proxy to track companies’ progress toward reducing whole life carbon emissions, committing to energy efficiency in buildings and committing to zero-carbon buildings/decarbonization of their own buildings.

It is important to note, however, that the framework of net-zero emissions at the building level does not necessarily require zero emissions, but rather allows for the possibility of offsetting some emissions. If carbon offsets must be used, it is of utmost importance that they are properly regulated and verified to remove CO2 from the atmosphere and are used after emissions are reduced as much as possible.

Number of countries in which electricity price per kWh is competitive with gas or oil for heating

The number of countries where the cost of heating with electricity is competitive with the cost of heating with fossil fuels signals whether shifting from fossil fuel-based to electric-powered devices is financially attractive to users.

Technologies to decarbonize buildings are available, and in many countries some level of support for their adoption exists. Fuel prices, however, impact the lifetime costs of these technologies and affect consumer choices. The number of countries where electricity costs are similar to fossil fuels for heating signals if a change from fossil fuel-based to electric-powered devices is financially attractive to users.

The cost competitiveness of electric heating, particularly with a highly efficient heat pump, versus a fossil gas boiler will be heavily influenced by factors such as grid stability —for instance, the frequency of outages — and the availability of oil or fossil gas. Employing fiscal instruments, such as removing fossil fuel subsidies or changing tax structures, could help incentivize a shift to zero-carbon technologies.

It is vital to ensure that every household can afford to make the switch to electric technologies and that economically vulnerable people are not stuck with antiquated, expensive equipment. It is also worth noting that electricity and fossil gas prices are not the only factors in the ultimate cost to the consumer — modern heat pumps are significantly more efficient than any other heating technology, so consumers will ultimately spend less to achieve the same level of comfort.

Unfortunately, global data on the cost-competitiveness of electricity with gas or oil for heating is unavailable, and prices vary by country. Reporting from government energy agencies provides a source for monitoring the prices of electricity and gas for heating.

Number of jobs in manufacturing, installation, repair and maintenance of low-carbon appliances

Job creation is an essential component of a just transition. There is no global data on how many people are currently working in the field of low-carbon appliances.

Job creation is an essential component of a just transition. Energy efficiency jobs are important to the global economy because they will provide the effort we need to retrofit buildings to use less energy.

Public spending on energy efficiency creates jobs for workers directly by creating demand for energy efficiency professionals, and indirectly by increasing demand for industries in the supply chains for these technologies. By enacting new efficiency standards for appliances such as washing machines and water heaters, we could create new jobs in installation, component manufacturing and other industries in the supply chain.

It is essential that new employment opportunities provide fair compensation, safe working conditions, equal opportunities and social protections. These jobs must be free of forced and child labor and provide employees the right to organize or discuss work-related issues. Retraining programs may be necessary for workers transitioning out of high-carbon industries.

There is no global data on the number of jobs that have been created in the field of low-carbon appliances (here meaning appliances that use less carbon than non-low-carbon versions), but some regional data is available. In the United States in 2018, more than 500,000 members of the energy-efficiency workforce were in jobs related to efficient appliances and lighting, over 350,000 in jobs related to building materials and insulation, and over 400,000 in jobs related to high-efficiency heating and cooling.

Photo credits

Photo by Florencia Potter on Unsplash