Lennox’ Ultra-Low NOx Gas Furnaces Earn Green Seal Certification for Innovation


Ultra-low nitrogen oxide (NOx) emissions decrease risk of respiratory problems and reduce impact on vegetation 

Washington, DC — Lennox’ award-winning Variable-Speed, Ultra-Low Emissions Gas Furnace (SL297NV) and Constant Torque, Ultra-Low Emissions Gas Furnace (EL195NE) have earned Green Seal’s Certification of Environmental Innovation, meeting a rigorous standard for transformative product innovation with furnaces that are energy efficient and produce significantly less harmful NOx emissions than market competitors. 

Lennox was the first HVAC company to sell a NOx furnace that emits 65% less nitrogen oxides than other products on the market, meeting a NOx emission level of 14 nanograms per joule or less – down from 40 nanograms per joule in previous models. Nitrogen oxide emissions, a precursor to smog, are one of six air pollutants regulated by the Environmental Protection Agency (EPA). Nitrogen oxides directly impact the lungs, causing airway inflammation, cough, wheezing, reduced lung function and increased risk of asthma. 

The biggest environmental impact from a furnace results from burning natural gas over the course of its 15- to 30-year lifespan. Natural gas is a fossil fuel and its combustion produces greenhouse gas emissions – the main cause of climate change. In addition to reducing NOx emissions, Lennox demonstrates high market leadership levels of energy efficiency by meeting the Qualification Requirements for ENERGY STAR v4.0. Increased energy efficiency contributes to less burning of natural gas over time, further reducing greenhouse gas emissions. 

Modern sustainability challenges demand modern solutions – that’s why Green Seal’s Environmental Innovation Standard measures improved health and environmental outcomes, not just material inputs,” said Doug Gatlin, CEO of Green Seal. “Furnaces are a vital feature in any home or building. Lennox has raised the bar for what we should expect from their furnaces and provided consumers an option to safeguard their health and air quality with a top-performing product. We are proud to award Lennox’ Ultra-Low NOx furnaces the Green Seal®.

In a marketplace crowded with meaningless and misleading marketing claims about the health and safety of products, Green Seal takes the guesswork out of identifying proven-safer, proven-greener options with guaranteed performance. Green Seal evaluates the health and environmental impacts of a product in all stages of its life cycle, from raw material extraction to manufacturing to packaging to how the product is used and disposed.

“We have been innovating in the sustainability space long before our ultra-low emissions family, specific to the green program in California. Lennox was already creating the most efficient HVAC system you can buy – gas or electric, which all ultimately tie to green initiatives and saving energy,” said Valerie Mastalka, Lennox Senior Product Marketing Manager, Heating.

Lennox’ Ultra-Low NOx furnaces meet California’s recent updated standards for all natural-gas-fired, fan-type residential central furnaces within certain parts of the state. 

Lennox products can be found at dealer locations in nearly every major U.S. city. More information on where to purchase Lennox’s Ultra-Low NOx furnaces can be found at https://www.lennox.com/locate/dealer-list


Green Seal’s Environmental Innovation Program is designed for manufacturers striving to advance product innovation for environmental good. The program allows manufacturers pioneering the integration of leading-edge design and performance aspects into their products to earn recognition for their innovations through a rigorous 3rd party certification. Find Innovation Certified products and learn more about the Environmental Innovation Program here.  


Lennox Residential, a division of Lennox International Inc. (NYSE: LII), is in constant pursuit of perfect air because we believe everyone deserves it. Whatever your version of perfect is, we can help make it happen. Offering some of the quietest and most efficient units on the market, the first ultra-low emissions furnace, and hospital-grade air filtration, Lennox has a history of designing innovative heating, cooling and indoor air quality products. Lennox’ approach to product design has earned it more Dealer Design awards than its competitors combined and multiple ENERGY STAR Most Efficient certifications. Lennox is a proud contributor to its communities, investing in the future of the HVAC industry and giving back through its corporate social responsibility program, Feel The Love. For more information about how Lennox is redefining air, visit Lennox.com/Residential.


Green Seal® is a global nonprofit organization with a mission to protect human health and the environment by accelerating the adoption of products that are safer and more sustainable. Since 1989, Green Seal has applied rigorous standards for health, environmental sustainability, and product performance to its certification programs to empower better purchasing decisions. Green Seal has certified thousands of products, services, and spaces from hundreds of leading companies and is specified by countless schools, government agencies, businesses, and institutions. Today, the Green Seal certification mark is a universal symbol that a product or service meets a high benchmark of health and environmental leadership. Visit greenseal.org or connect with Green Seal on X and LinkedIn.