What are the Low Nox Furnace Requirements for Colorado in 2026?

In Colorado, the requirements for furnaces are centered around strict air quality and emission standards set by the Colorado Department of Public Health and Environment. While the provided text details existing and upcoming standards, the specific requirements for 2026 include:

Emission Limits: New furnace installations, particularly in the Front Range and Denver metro areas, must meet ultra-low NOx regulations. These regulations mandate emission levels of 14 nanograms per joule (ng/J) or lower. Some specific models, like the Compact A801X, already target levels under 10 ng/J to ensure compliance.

Efficiency and Certification: To meet state-wide standards and quality benchmarks, furnaces should be high-efficiency models, often reaching up to 96% to 98% AFUE. Homeowners are encouraged to select ENERGY STAR certified units, which verify both efficiency and low NOx levels.

High-Altitude Performance: Due to Colorado’s average elevation of 6,800 feet, furnaces must be rated for high-altitude performance (above 5,000 feet). This is critical to prevent incomplete combustion and excess emissions.

Local Compliance and Permits: Installations in urban areas like Denver, Aurora, and Colorado Springs must adhere to the 2018 building code updates for low-emission appliances. Homeowners must also obtain necessary permits and air quality approvals during the installation process.