The building sector contributes to 30% of the world’s final energy consumption and to 28% of the world’s energy-associated carbon emissions. Considering this, the paper offers a unique technical framework for the development of building energy codes, where each of the 138 countries contributes its ‘fair’ share towards a below 2°C scenario–aligned global buildings sector. Developing an energy use intensity (EUI) model, also referred to as the global Building Stock Energy Model, the paper predicts the energy efficiency levels for 138 countries’ building stocks in order to meet the Paris Agreement’s below 2°C scenario (B2DS).

The sector is failing to meet its climate change target set by the International Energy Agency, known as the Sustainable Development Scenario. Whilst current building energy codes and policies have reduced the sector’s energy use per unit of floor area, they have not reduced the sector’s overall energy demand. This is due to current policies’ disregard of growth in population size and levels of income which both lead to increases in built-up area and increased spending on energy services in buildings. Thus, the paper contends that energy codes need to be aligned with global climate change targets whilst considering the sector’s expansion. The paper’s EUI-model realises this vision.

The model determines the necessary energy efficiency levels (EUIs in kWh/m²·year) to meet the B2DS for 138 countries’ newly constructed and existing residential and non-residential building stock under a low gross domestic product (GDP) and high GDP scenario. The modelling period is between 2017-2060 and assumes a globally equitable annual building energy allowance per person. The framework envisions that all countries must achieve dignified levels of human development. Therefore, the reduction of greenhouse gas emissions is dependent upon the country’s historical responsibility and its capacity to act, determined by the country’s per capita income levels.

The results indicate that to meet the B2DS target whilst maintaining opulent lifestyles within buildings and accommodating the sector’s growth requires significant advancements in energy efficiency, surpassing any advancements in the past. Expectedly, lower EUIs were necessary under the high GDP scenario, contrasting the low GDP scenario. The results also demonstrate that developed countries’ building stocks will need to meet lower EUIs as they are above the per capita energy ‘budget’ whist developing countries are below it.

Policymakers can use the relevant technical pathways demonstrated with the EUI-model as the foundation for building energy codes and policy interventions that are consistent with a B2DS target. To achieve the B2DS target, the sector needs stringent building energy codes, and it is likely that this will entail a downscaling of the ‘needs’ the sector seeks to satisfy and its size. This highlights the pertinence of using degrowth concepts in the building sector to avoid the climate change impacts of warming above 2°C. Socioeconomic interventions from policymakers to align the sector with the B2DS target include imposing penalties for excessive energy consumption through tariff restructuring and creating incentives for passive and climate resilient design.