92+% Low & Ultra Low NOx (California)

Meet California’s NOx emission requirements with our 92%to 98% AFUE, PVC-vented (condensing) gas furnaces, available in Low NOx and Ultra-Low NOx (ULN) versions for code-compliant installations depending on county.

What is NOx?
NOx stands for Nitrogen Oxides — smog-forming pollutants produced during combustion that contribute to ground-level ozone and respiratory irritation. California air districts set appliance emission limits to reduce NOx and improve air quality.

What is AFUE (briefly)?
AFUE = Annual Fuel Utilization Efficiency. A 92%+ AFUE furnace converts at least 92% of its fuel into usable heat, with less than 8% lost through exhaust gases. These are high-efficiency PVC-vented condensing furnaces that extract additional heat from combustion gases using a secondary heat exchanger — ideal for homeowners seeking maximum efficiency and reduced emissions.

Where Ultra-Low NOx (14 ng/J) Furnaces Are Required in California

Two California air districts currently require Ultra-Low NOx (14 nanograms per Joule) emissions for residential fan-type central furnaces:

  1. South Coast AQMD (Rule 1111 – 14 ng/J)
    Counties/areas: Most of Los Angeles County (except Antelope Valley), all of Orange County, and the western/urban portions of San Bernardino and Riverside Counties. South Coast AQMD Rules

  2. San Joaquin Valley APCD (Rule 4905 – 14 ng/J)
    Counties: San Joaquin, Stanislaus, Merced, Madera, Fresno, Kings, Tulare, and the valley portion of Kern County. San Joaquin Valley APCD Rules

Translation for shoppers/installers:

  • If your install address is in South Coast AQMD or San Joaquin Valley APCD, select an Ultra-Low NOx (14 ng/J) model to pass inspection.
  • Elsewhere in California, a Low NOx model typically meets local requirements.
  • Outside California, few states have residential furnace NOx mandates, but always verify with your local air-quality or building authority.

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