Colorado's New NOx Emission Law to Impact Home Appliance Choices Starting 2026

Beginning January 1, 2026, a new Colorado state regulation aimed at reducing nitrogen oxide (NOx) emissions will change how homeowners purchase and replace certain gas-powered appliances. The regulation applies to new installations of certain gas appliances, and while existing systems are not required to be replaced simply because of the law, once a system fails or is removed, homeowners will need to comply with the updated standards. Gas furnaces and gas water heaters installed after January 1, 2026, must meet lower NOx emission thresholds than many current models.

This new NOx law is part of Colorado's broader effort to improve air quality and to reduce emissions that contribute to smog and respiratory issues. While the law does not ban natural gas outright, it places stricter limits on emissions from newly installed gas appliances, which will influence product availability, pricing, and installation timelines. Some traditional gas furnaces and water heaters that are commonly installed today may no longer be legal to install after the deadline. Low-NOx gas appliances and alternative technologies often come with higher purchase and installation costs compared to older models.

For homeowners considering a new gas furnace, the NOx law introduces important planning considerations. Standard-efficiency gas furnaces may be phased out as many older-style furnaces do not meet the new emission requirements and will no longer be installable. High-efficiency and ultra-low-NOx models may be required, and these systems often cost more and may have longer lead times. Cold-climate heat pumps have improved significantly and can now handle Colorado winters when properly designed, making them a common alternative. Switching from gas to electric heating may require panel upgrades or additional electrical work.

Water heaters are also affected by the NOx regulation. Traditional gas water heaters may no longer qualify as these are among the most common and affordable options today, but many will not meet new standards. Condensing gas or heat pump water heaters may become the default, though these systems are more efficient but come with higher upfront costs. Newer systems can require different clearances, venting, or drain access. Planning ahead can prevent disruptions, as waiting until a water heater fails could limit choices and extend downtime.

If a furnace or water heater fails in winter after January 1, 2026, homeowners may have fewer immediate replacement options available. Many homeowners may be encouraged—or effectively required—to consider electric heat pumps or heat pump water heaters, depending on their home's setup. The company Brothers Plumbing, Heating & Electric is committed to helping homeowners navigate these changes with clear information and practical guidance. Their goal is to make sure people understand their options so they're not caught off guard when it's time to replace a furnace or water heater. Every home is different, and some homeowners will still qualify for compliant gas systems, while others may benefit more from electric or hybrid options.