Building energy codes could help Global South cities cut emissions and climate risk

Building energy regulations could become a stronger climate tool for the Global South, but many countries still lack mandatory codes or struggle to enforce rules that reflect local climate, construction and economic realities, claims new research published in Encyclopedia. It argues that stronger, context-specific building energy efficiency codes can reduce energy demand, cut emissions and help rapidly urbanising regions build more resilient cities.

The study, titled The Real-World Use of Building Energy Regulations as a Mechanism to Accelerate Climate Resilience in the Global South, uses a two-tiered literature review, including an exploratory review of recent building energy code research and a Systematic Quantitative Literature Review of mandatory building energy efficiency codes in 18 Global South countries, to develop a decision-support prototype called the Sustainable Level Indicator Model, Matrix, and Map (SLIM3).

Weak code coverage leaves fast-growing cities exposed

Buildings account for a large share of global energy demand and carbon dioxide emissions. The global building sector is expected to expand sharply through 2050 and much of that expansion will take place in the Global South, where population growth, urbanisation and rising energy use are already increasing pressure on electricity grids, infrastructure and public finances.

This growth makes building energy regulation more urgent, not less. Energy-efficient buildings can reduce operational energy use, lower greenhouse gas emissions, improve thermal comfort and ease pressure on power systems. They can also reduce energy costs for households and businesses, which matters in regions where energy poverty and unreliable supply remain persistent concerns.

The regulatory landscape remains uneven. Many Global South countries have no known building energy efficiency codes. Others have voluntary rules, partial coverage or mandatory systems that are inconsistently enforced. Even where codes exist, they often do not fully account for local climate zones, construction methods, institutional capacity or socio-economic conditions.

The gap weakens the role of building energy codes as climate-resilience instruments. Codes imported or adapted from Global North systems may assume stronger technical capacity, more formal construction practices, larger enforcement budgets and better institutional coordination than many Global South settings can provide. As a result, the same regulatory language may not deliver the same real-world results.

The review stresses that building energy codes are not just technical documents. They depend on systems, structures and stakeholders. Systems refer to the procedures that support implementation and enforcement, including inspections, verification and funding. Structures refer to the levers that drive compliance, such as penalties, incentives and code updates. Stakeholders include regulators, building owners, developers, designers, contractors and compliance officers.

When any of these parts are weak, the code’s impact declines. A well-written rule may fail if local authorities lack trained staff. A technically sound requirement may be ignored if there are no penalties. A code may be unsuitable if it does not reflect climate conditions or common building practices. The authors argue that Global South countries need regulatory models that are both ambitious and workable.

The study also points to a global implementation problem. Mandatory building energy codes remain absent in many countries, even as new floor space continues to be added. This means millions of new buildings may be constructed with little attention to future energy demand, cooling needs or climate stress. Once inefficient buildings are built, correcting them later through retrofits can be more expensive and politically harder.

For rapidly growing cities, that delay can lock in emissions and infrastructure strain for decades. The review warns that building energy codes must keep pace with urban expansion if they are to support climate resilience rather than merely respond to damage after the fact.

Evidence shows codes can cut energy use, but design and enforcement matter

The review finds that building energy codes can deliver real energy savings, but their results vary widely by country, building type, code design and enforcement quality. The authors discuss studies showing that updated or better-applied codes can reduce heating and cooling demand, improve building envelope performance and support more efficient lighting, water heating and HVAC systems.

Some examples show modest gains, while others show larger savings when codes are more comprehensive or when existing buildings are retrofitted to meet energy requirements. The pattern is clear: codes work best when they cover the whole building system and when they are regularly updated as technologies, climate risks and construction practices change.

The paper also highlights the problem of energy performance gaps. These occur when buildings consume more energy in real use than regulations or models predicted. Such gaps can emerge from weak code assumptions, poor construction quality, changing occupancy patterns, inadequate inspections or user behaviour that codes did not anticipate.

The finding is critical because many building energy regulations still rely on static assumptions. They may not account for how buildings are actually occupied, how households respond to heat, how informal construction works, or how climate change will alter cooling and comfort needs. The authors argue that codes must become more dynamic and context-based.

Climate zoning is one key area. Building performance depends heavily on local climatic conditions, but the review notes that zoning methods vary and may not always reflect the diversity of Global South climates. A code that treats regions too broadly can lead to requirements that are too weak in one area and too costly or inappropriate in another.

The review also argues that building energy codes should expand beyond narrow operational energy targets. Future-ready codes may need to address life-cycle energy use, embodied carbon, renewable energy, passive cooling, shading, solar systems, material choices, building size and retrofit strategies. These additions can help shift codes from minimum compliance instruments to broader tools for decarbonisation.

Compliance remains a major barrier. Studies reviewed in the paper identify recurring problems, including limited inspection capacity, weak enforcement budgets, fragmented national and local coordination, lack of awareness among professionals, absence of penalties, political discontinuity and limited incentives for developers to exceed minimum standards.

The authors identify several opportunities.

• Governments can train code enforcement personnel, publish technical manuals, develop validated material catalogues, create building energy labelling systems, use virtual inspections where appropriate, apply penalties for non-compliance and provide incentives for retrofits or high-performing buildings. Local governments can also use compliance rates as a monitoring indicator.
• Stakeholder engagement is very important. Developers, building owners, design professionals and contractors need to understand not only what codes require, but why compliance matters. Without awareness and practical support, energy regulations may be seen as paperwork rather than as a route to lower costs, better buildings and climate protection.

The review also points to the importance of regular code updates. Climate change, new technologies and changing urban conditions can quickly make older rules outdated. Codes that were once adequate may become less effective as heat stress rises, cooling demand grows and construction methods change.

SLIM3 aims to help countries build context-specific energy codes

The SLIM3 prototype, a decision-support tool designed to help Global South countries compare and strengthen building energy codes, is built from an analysis of mandatory building energy codes in 18 Global South countries covering 20 code documents.

The authors first identified 55 Global South countries based on projected 2050 urban population and greenhouse gas emissions. These countries represent a large share of future urban growth and emissions in the Global South, making them central to any climate-resilient building agenda. The study then examined climate zones across the target population to ensure that the tool reflected the region’s climatic diversity.

Thereafter, the researchers focused on countries with mandatory building energy codes across whole building sectors. They compared technical requirements and organised them into a structured framework, covering areas such as building classification, climate zoning, building envelope performance, glazing and shading, cooling, lighting, solar water heating, renewable energy and other design strategies.

SLIM3 is designed to let users filter information by code status, climate classification, energy-efficiency criteria and quantitative requirements. In practical terms, it gives policymakers and practitioners a way to compare what similar countries require, identify missing provisions and benchmark possible improvements.

This is particularly important for countries without building energy codes, or those looking to revise weak ones. Rather than copying Global North models, they can compare approaches from countries with more similar climate, income, urban growth and institutional conditions. The paper frames this as South-South learning, where Global South countries can draw from one another’s regulatory experience.

The authors note that SLIM3 is just a prototype that needs testing, refinement and validation across different settings. However, the idea addresses a real policy gap: many countries need accessible, comparable and context-sensitive regulatory information, especially where technical resources are limited.

The review is based on literature, policy documents and comparative regulatory analysis rather than new building performance measurements. The SLIM3 tool is also still in development, meaning its usefulness will depend on future testing with policymakers, regulators, built-environment professionals and contractors.