Across the world, most buildings continue to depend on fossil fuels like natural gas for heating, driving a significant share of global greenhouse gas emissions. Climate change is reversing traditional energy use patterns, reducing heating demand while sharply increasing the need for cooling.
By 2050, nearly every region will face extreme heat events that heighten public health risks and intensify reliance on energy-intensive air-conditioning systems. As the built environment faces escalating demand, improving efficiency and accelerating the adoption of low-carbon heating and cooling technologies is essential to reduce fossil fuel dependency and mitigate emissions.
This article examines the environmental challenges linked to current heating and cooling practices and highlights the urgent need for innovation, investment, and cross-sector collaboration to advance energy-efficient technologies.
Why is decarbonizing heating and cooling in buildings essential?
Heating and cooling account for a major share of building energy use and represent one of the most challenging sectors to decarbonize. The following factors highlight why accelerating the transition to low-carbon systems in the built environment is urgent.
Air pollution
Heating and cooling systems are among the largest contributors to air pollution. Across the EU, they account for a significant share of harmful emissions, making the sector a major environmental and public health concern. The heating and cooling of buildings generate:
– 73% of fine particulate matter (PM2.5)
– 33% of nitrogen oxides (NOx)
– 2% of ammonia (NH₃)
– 18% of non-methane volatile organic compounds (NMVOCs)
– 61% of carbon monoxide (CO)
– 49% of sulfur dioxide (SO₂)
Increased energy consumption
Global energy use for space cooling has been growing rapidly averaging around 4% annually since 2000. This surge places additional strain on electricity systems, as cooling demand typically peaks during hot days, increasing the risk of power shortages.
Since 1990, energy consumption for air conditioning has more than tripled, contributing to higher greenhouse gas emissions and worsening urban heat island effects. Without widespread adoption of efficient cooling technologies and better building design, global electricity demand for space cooling could rise by up to 40% by 2030, further challenging grid stability and climate goals.
Refrigerant leakage
Space cooling systems also contribute to greenhouse gas emissions through refrigerant leaks. These refrigerants, particularly hydrofluorocarbons (HFCs), can have a global warming potential thousands of times greater than CO₂.
Commonly used across air conditioners, heat pumps, refrigerators, freezers, and vehicle cooling systems, HFCs belong to a class of gases known as F-gases. When released whether due to equipment leaks, poor maintenance, or illegal venting, they escape into the atmosphere and act as potent greenhouse gases, exacerbating climate change
CO2 emissions
Space and water heating represent the largest sources of direct carbon emissions in the building sector, making up over 80% of total emissions. In 2022, these activities produced roughly 4.2 gigatonnes of CO₂, with about 2.4 gigatonnes stemming directly from the onsite combustion of fossil fuels such as natural gas, oil, and propane used for heating purposes.
However, scaling energy-efficient and low-carbon heating and cooling systems faces multiple barriers, including high upfront costs, slow adoption rates, and insufficient policy support. Overcoming these challenges is critical to decarbonizing the built environment.
It also highlights the complex task of balancing energy demand with air quality, affordability, and climate objectives, underscoring the urgency of accelerating the transition to cleaner and more efficient technologies.
Accelerating the transition to low-carbon heating and cooling
Heating and cooling account for a major share of global building emissions, yet progress toward decarbonization remains slow. Rising energy demand, fossil fuel dependence, and inefficient infrastructure continue to hinder climate goals.
Accelerating the transition to low-carbon systems is critical to close the emissions gap. Investment and innovation must focus on scalable technologies such as high-efficiency heat pumps, district systems, and thermal storage that can replace combustion-based solutions.
Startups have a pivotal role in developing cost-effective systems, optimizing performance, and integrating renewable energy. Strategic investment, clear regulation, and technology partnerships will be essential to modernize the sector. These steps will help speed up with decarbonization of heating and cooling in the Net Zero transition.
