The CIBSE decarbonisation event this summer highlighted the challenges and opportunities in decarbonising our heating and cooling demand. This is not just the case in the UK – countries around the world are on a similar trajectory – so there is a great opportunity to learn from each other in research, policy and technology.
Heating and cooling account for a significant portion of global energy consumption and carbon emissions. In the UK, space heating alone is responsible for more than 30% of total energy use and around 17% of national greenhouse gas emissions.
As the country strives to meet its 2050 net zero target, decarbonising heating and cooling systems is an urgent and complex challenge. Around the world, countries are deploying innovative approaches tailored to their climates, energy infrastructures and policy contexts.
Learning from these international efforts can help the UK refine its own strategies and avoid costly mistakes or long-lasting, unintended consequences.
The UK landscape
Heating: navigating transition
The UK’s heating infrastructure is dominated by natural gas, with around 85% of homes connected to the gas grid. Decarbonising such an established infrastructure is no small task. The government’s Heat and Buildings Strategy, published in 2021, sets out plans to support heat pumps, hydrogen trials and heat networks. Yet progress remains incremental, with high upfront costs, skills shortages and public uncertainty.
Heat pumps are positioned as a cornerstone of domestic decarbonisation, particularly in off-Grid areas, but deployment lags far behind targets. According to the Microgeneration Certification Scheme, fewer than 200,000 heat pumps were installed in the UK in 2023, well short of the government’s aim of 600,000 per year by 2028.
Meanwhile, heat networks are being expanded and modernised, with a focus on low carbon heat sources such as geothermal, waste heat and large-scale heat pumps. The Green Heat Network Fund and zoning regulations promise to accelerate deployment, but questions remain around scalability, consumer protections and integration with existing buildings.
Cooling: a growing concern
Historically, cooling demand in the UK has been low. However, with the increasing frequency of heatwaves and a warming climate, demand is rising fast, particularly in commercial and healthcare sectors. Air conditioning use is set to triple by 2050 globally, with the UK already seeing a sharp rise in installations.
Passive cooling strategies, building fabric improvements and district cooling systems must form a core part of the UK response. Retrofitting existing buildings with passive design features, such as shading and ceiling fans, can reduce reliance on mechanical cooling and improve resilience during extreme weather events.
Learning from the rest of the world
Other countries provide valuable case studies. In Scandinavian nations such as Sweden and Denmark, district heating powered by biomass, waste heat and renewable electricity is mainstream. Nearly 65% of Danish households are connected to highly efficient district heating systems, increasingly powered by surplus wind energy. Denmark’s approach to heat network regulation and public ownership has ensured long-term planning, affordability and consumer trust.
Germany has taken a different approach, offering generous incentives for heat pump installation, with mandated use in new buildings from 2024. A strong focus on training and standards supports the development of a skilled workforce capable of delivering high-quality installations.
In Asian countries such as Japan and South Korea, heat pump technologies experiment with CO₂ refrigerants to improve environmental impact, while large-scale district cooling is integrated into urban developments, highlighting the potential for district-level solutions in dense urban environments.
Developing countries, too, offer insights, particularly in integrating passive design and low-tech cooling. In India, the national Cooling Action Plan encourages thermal comfort through vernacular architecture and low-energy building design. These approaches remind us that decarbonisation does not always depend on high-tech or mechanical solutions to be effective.
Policy, technology and behaviour: an integrated approach
Globally, one clear message emerges. No single technology or policy will decarbonise heating and cooling on its own. Success depends on a systems-level approach that integrates supply, demand, policy, technology and user behaviour.
For the UK, this means continuing to invest in diverse heating and cooling technologies, while addressing demand through building retrofit and energy efficiency. It also means fostering the skills, standards and occupant engagement needed to build knowledge, trust and ensure uptake.
Policymakers must also address the unique challenges of the UK’s building stock. The prevalence of older, poorly insulated homes presents a barrier to electrification. Mass retrofit programmes, particularly for insulation and ventilation, are essential. Standards, such as Energy Peformance Certificates and the Minimum Energy Efficiency Standard, can help drive improvements, but support for low-income households will be critical to ensure equity.
CIBSE leadership in a global context
CIBSE Members will play a crucial role in this transition. From design to commissioning and post-occupancy evaluation, engineers must bring a deep understanding of technology and human behaviour.
They must be continuous global learners. International collaboration, through organisations such as the International Code Council, Rehva, ASHRAE and CIBSE’s own non-UK chapters, offer a rich forum for knowledge exchange.
By embedding these lessons into local policy, design and delivery, we can accelerate the decarbonisation of heating and cooling in a way that is effective, equitable and resilient.
About the author
Dr Anastasia Mylona, CIBSE technical director