Greenhouse Gas (GHG)

Greenhouse gases (GHGs) are gases that trap heat in the Earth’s atmosphere — a process known as the greenhouse effect. While some GHGs occur naturally, human activities have drastically increased their concentrations, intensifying the effect and contributing to global climate change.

Certain GHGs can remain in the atmosphere for decades or even centuries, making them a key focus in long-term climate strategies for both governments and businesses.

Common Greenhouse Gases List

The following gases are commonly associated with climate change and vary significantly in both origin and environmental impact:

• Carbon dioxide (CO₂) – From fossil fuel combustion, the largest contributor to climate change
• Methane (CH₄) – From agriculture, landfills, and gas production
• Nitrous oxide (N₂O) – From agricultural activities and fuel combustion
• Refrigerants used in HVAC systems
  • Hydrochlorofluorocarbons (HCFCs) – e.g., R-22, phased out for ozone and climate impact
  • Hydrofluorocarbons (HFCs) – e.g., R-410A, high GWP, being phased down
  • Hydrofluoroolefins (HFOs) – e.g., R-454B, next-generation refrigerants with ultra-low GWP
• Naturally occurring gases – e.g., water vapor and ozone (with less controllable impact)

For more on HVAC refrigerants, see Using R22 Refrigerant and Its Alternatives in HVACR Systems.

Why Greenhouse Gases Matter to Your Facility

Increased concentrations of GHGs are contributing to climate change, which manifests as

• More extreme weather events: heat waves, hurricanes, and floods
• Economic impacts: infrastructure damage, higher energy costs, and operational disruptions
• Rising sea levels and decreased biodiversity
• Stricter regulatory frameworks for buildings and emissions

For facilities and sustainability managers, reducing your building’s GHG emissions is not just environmentally responsible; it’s an operational imperative.

HVAC Systems and GHG Emissions

According to the Intergovernmental Panel on Climate Change (IPCC), the United Nations panel for assessing the science related to climate change, carbon dioxide is the greenhouse gas that has the biggest impact. The most common source of carbon dioxide since the beginning of the industrial revolution is human activities, like burning fossil fuels for heating and transportation.

Carbon Emissions from Heating

Fossil fuel-based HVAC systems (e.g., gas furnaces or boilers) emit carbon dioxide directly. And if your electric company burns fossil fuels to generate electricity, an inefficient electrified HVAC system will indirectly be responsible for higher carbon emissions.

Electric heat pumps produce zero on-site carbon emissions and, when paired with renewable or low-carbon electricity, can dramatically reduce total emissions.

Refrigerant Emissions

HVAC refrigerants are basically powerful greenhouse gases if leaked into the atmosphere. Older systems using R-22 or R-410A have high global warming potential (GWP). Transitioning to modern systems with low-GWP refrigerants like R-454B helps cut emissions significantly.

Trane’s Commitment to GHG Emissions Reduction

At Trane, we’ve aligned our HVAC innovation with long-term climate and regulatory goals. Through our Gigaton Challenge, we’ve pledged to help reduce one billion metric tons of carbon emissions from customer operations by 2030, which is the equivalent to the annual emissions of Italy, France, and the U.K. combined.

How we’re doing it:

• Transitioning all new residential and commercial equipment to low-GWP refrigerants
• Innovating higher-efficiency HVAC systems to reduce emissions
• Educating our clients about sustainable HVAC solutions

What You Can Do: Reduce GHGs at the Building Level

If your facility operates older HVAC systems, upgrading to a heat pump system with a low-GWP refrigerant can deliver measurable GHG reductions while lowering energy consumption and utility costs. It can also move your organization into alignment with sustainability or net-zero goals and compliance with federal and state refrigerant regulations.

Resources for GHG Emissions Reduction

• Energy Services
• Things to know: Decarbonization and Ultra Low NOx in California
• Case study: Solae LLC
• Case study: EnerSys puts Ambition into Action with Enterprise Decarbonization Program focused on Electrification
• Case study: U.S. Department of Agriculture Forest Service Pacific Southwest Region
• Case Study: Decreasing Carbon Emissions at Grand Hyatt New York: A Roadmap for Creating Sustainable Hotels

Work with Trane’s commercial HVAC experts to develop a customized roadmap toward a lower carbon footprint and more efficient building operations.