Authors and contributors
IEA (2019), "Tracking Buildings", IEA, Paris https://www.iea.org/reports/tracking-buildings
Constructed floor space in buildings worldwide has increased by 65% since 2000, reaching nearly 240 billion m2 in 2018. Yet, average energy use per m2 has declined by only 25%, meaning progress did not offset floor area growth.
Building envelope performance improvements are critical to achieve the Sustainable Development Scenario (SDS), but most countries have still not made them an explicit policy priority.
As of 2018, only 69 countries had a mandatory or voluntary building energy code, and around 85 had building energy certifications: this includes 36 countries with mandatory building energy certification policies and 20 with widespread voluntary building energy certification policies or programmes, with the remainder having only a few voluntary projects.
A wide range of building policy packages to improve building envelope performance was introduced in 2017 and 2018, but these measures were not enough to keep up with rapid growth in global floor area. In fact, most changes in 2017‑18 were updates in countries that already had energy codes. In addition, strength remains either limited or voluntary in most countries with codes in place.
A handful of countries introduced or were developing building energy codes in 2017‑18, and several implemented building energy certification or incentive programmes.
For instance, India took a step forward in 2018 with development of its first national model building energy code for residential buildings.
The draft Energy Conservation Building Code for Residential Buildings was designed to be enforced simply while also improving occupant thermal comfort and enabling the use of passive systems.
Nigeria also launched its first building energy code in September 2017, and India updated its 2007 Energy Conservation Building Code for commercial buildings.
In Argentina in 2017, the federal government developed a national standard for thermal envelope performance that applies to social housing. This social housing policy is the first national standard for building energy performance.
Several other countries are also working on their first national building energy codes, for example Mexico, in collaboration with the International Code Council. The building energy codes upgrades under way in South Africa incorporate climate zone differentiation.
Two out of three countries lacked mandatory building energy codes in 2018
Progress on energy certification programmes gained speed in several countries in 2017‑18.
- Canada’s Green Building Council launched a dedicated Zero Carbon Building Standard in May 2017, making carbon emissions the key indicator for building performance.
- In Ghana, the Eco-Communities and Cities National Framework was launched in March 2017 to become an integral part of the National Housing Policy.
- Brazil’s Green Building Council also launched a Zero Energy Standard in 2017, and 11 pilot projects will evaluate the standard across five states.
Less than a third of countries had building energy certifications in 2018.
Nevertheless, building energy certifications still fall short of promoting major change in the buildings market, as they are typically voluntary or cover only a small number of buildings.
High-performance buildings such as near-zero energy buildings (nZEBs) typically make up less than 5% of construction in most markets today. Progress on constructing high-performance buildings has advanced in a several countries, however.
France is a leader in the nZEB market, with a building code that requires all new constructions to fall under its nZEB definition.
In Austria, Belgium and Italy, more than 20% of new residential constructions in 2018 were nZEBs.
The typical energy renovation rate is 1‑2% of the building stock per year, with average energy intensity improvements generally less than 15%.
One notable development was the expansion in 2017‑18 of the Energiesprong programme, which is now active in four countries – France, Germany, the Netherlands and the United Kingdom. This innovative initiative seeks to achieve affordable zero-energy building retrofits by leveraging private financing repaid through energy savings in public buildings.
Progress is being made on other fronts as well, such as the European Union’s revision of the European Performance of Buildings Directive in June 2018 to accelerate the renovation of existing buildings.
In 2017 the International Organization for Standardization (ISO) published its ISO 52000-1 standard for energy performance of buildings, which establishes a systematic and comprehensive structure for assessing building energy performance. But harmonisation is only one step towards the compulsory energy certification that is necessary.
Urgent steps to introduce, upgrade and enforce building energy codes are needed to achieve climate targets. They will need to accommodate rapid growth in the sector and improve thermal comfort in buildings without significantly raising energy demand and resultant emissions.
Immediate action is needed to expand and strengthen mandatory building energy codes. Knowledge-sharing across countries to establish, improve and enforce building energy codes can help make high-performance construction a standard practice.
Sharing know-how can also ensure the use of best practices and suitable technologies, for instance using enhanced insulation techniques in cold-climate countries to reduce thermal losses, and using cool roofs, shading and low-emissivity (low-e) windows to reduce cooling energy needs in hot regions.
In advanced economies such as the United States and the European Union, buildings already standing today will likely make up a considerable share of the total stock to 2050.
Establishing large-scale refurbishment of buildings should therefore be a key policy priority in the coming decade. Greater effort needs to be focused on compiling a comprehensive and sound evidence base of technical and economic case studies, as well as pilot programmes that demonstrate actionable results.
High-performance, near-zero energy buildings are essential to fulfil the Sustainable Development Scenario (SDS) ambitions.
Countries should set detailed market targets on building energy performance to send clear signals to industry and investors. This can be done by leading by example, such as requiring high-performance construction for new public buildings and offering financial incentives to encourage market uptake of high-performance solutions.
Governments can also support industry-led initiatives such as the Advancing Net Zero project by the World Green Buildings Council, which calls on businesses, organisations, cities, states and regions to reach net-zero carbon operating emissions by 2030 and to advocate for 100% net-zero carbon buildings by 2050.
Implementing high-performance construction and renovation packages will require improved access to financing and innovative business models that bring borrowers, lenders and regulators together.
Governments can enable this through policy interventions that shape market rules to improve access to financing and de-risk clean energy investment.
This can include the use of tax exemptions, grants, loans, auctions and obligations. Governments can also work with the finance sector, banks and investors, among others, to create a common classification scheme and solid evidence base for such investments.
Boosting construction of high-performance buildings by 2030 will require innovative technical solutions and business models to meet the energy needs of a variety of building types in multiple regions. Innovation is also needed to improve investment returns for high-performance building technologies, taking energy prices, labour costs and the nature of the building design or retrofits into account.
Airtightness is a strong determinant of energy demand in buildings. In cold climates, exfiltration through the building envelope accounts for a significant share of a building's thermal losses. Infiltration of cold air can also cause mould and lead to material degradation, which affects the health of occupants and the lifetime of the building.
Proper control of air flows and ventilation is even more important in hot climates to keep buildings healthy and comfortable. Enhanced building designs can allow natural ventilation and maintain comfortable temperatures without mechanical assistance. Ventilation systems can also help keep buildings healthy by removing indoor air pollutants and controlling the thermal environment.
Windows are estimated to be responsible for 5‑10% of total energy consumed in buildings – and even higher for certain buildings (e.g. with all-glass facades). Highly insulated windows have great potential to reduce energy consumption in new buildings and in structural retrofits.
Maximising/minimising solar gains (depending on the region) can significantly reduce heating/cooling demand, especially in buildings with considerable glass. Optimising visible light transmittance can reduce lighting energy demand.
Integrated storage and renewable energy technologies for buildings (e.g. pairing clean energy production with local storage and energy use) can address multiple climate change mitigation objectives at once. One such solution is thermal energy storage, which can displace cooling and heating demand while also enabling higher penetration of variable renewable sources in the energy system. Integrated renewables (e.g. on a building's facade) can also enable greater energy production, as the related area usually is much larger than rooftop space.
- BPIE (Buildings Performance Institute Europe) (2018), "Building 4 people: Quantifying the benefits of energy renovation investments in schools, offices and hospitals. Methodology and results", BPIE, Brussels.
- Buso, T. (2017) (2017), "Nearly zero energy multi-functional buildings: Energy and economic evaluations", PhD thesis, Politecnico di Torino, pp. 390, http://dx.doi.org/10.6092%2Fpolito%2Fporto%2F2690913.
- Journal des énergies renouvelables (2018), "Une sélection de 40 bâtiments remarquables", Architecture Solaire Architecture d'Aujourd'hui, No. 245, https://www.journal-enr.org/journal/journal-des-energies-renouvelables-n-245/.
- Passipedia (The Passive House Resource) (2019), "Economic feasibility of Passive House design", https://passipedia.org/basics/affordability/economic_feasibility_of_passive_house_design.