Planning Ahead for Furnace Replacement Before Colorado’s 2026 Rule Changes
Starting in 2026, new regulations in Colorado will impact which types of furnaces can be sold and installed in homes. These changes are designed to reduce harmful emissions and improve air quality across the state.
The good news for Denver–Boulder metro area homeowners is that there will be ample furnace inventory available for some time after the rules take effect, giving you flexibility and peace of mind.
Read on to learn about what’s changing, what it means for local homeowners, and why it makes sense to start planning now if you think a furnace replacement might be in your near future.
What’s Changing in Colorado in 2026
Beginning January 1, 2026, all new gas furnaces sold or installed in Colorado will need to meet Ultra-Low NOx (ULN) or ENERGY STAR® certification standards. ULN furnaces produce 14 nanograms per joule (ng/J) of nitrogen oxide emissions or less, significantly reducing pollutants that affect air quality.
State agencies will be responsible for enforcing these new requirements, and violations could carry penalties of up to $2,000. However, any furnaces already in Colorado before the deadline can still be installed until the existing inventory is depleted, providing a smooth transition period for Denver–Boulder metro area homeowners.
What This Means for Homeowners
For most homeowners, these changes will feel gradual rather than abrupt. Lennox and other major manufacturers expect furnace inventory to last several months after the new rules begin — likely between three and six months, depending on demand.
The short of it is that you don’t need to replace your furnace immediately, but if yours is aging or has been showing signs of wear, it may be smart to start planning ahead. Thinking proactively allows you to explore your options, understand new efficiency standards, and take advantage of available rebates or incentives before they potentially change in 2026.
Timeline of Upcoming Shifts
The new furnace standards officially start on January 1, 2026, when all furnaces installed in Colorado must be ULN or ENERGY STAR® rated with at least 95% Annual Fuel Utilization Efficiency (AFUE). A few months later, on July 31, 2026, the next update (ENERGY STAR® 5.0) will take effect. Under this version, the minimum AFUE for Colorado and other northern regions will rise to 97%.
Additionally, some rebate programs offered through Xcel Energy and other state or federal agencies may be updated or adjusted around this time. Staying informed will help ensure you get the best possible value when you decide to replace your system.
Why These Rules Exist
Gas furnaces are currently one of Colorado’s largest sources of nitrogen oxide (NOx) emissions. The purpose of this change is to reduce these emissions, which can have a significant impact on local air quality as well as public health.
Colorado’s rules also align with a growing national trend toward more environmentally friendly and efficient heating systems. It’s worth noting that the state plans to continue reviewing standards before 2030, which could bring even stricter emissions requirements as industry technology continues to evolve.
Key Considerations for Homeowners
These changes are significant, but there’s no need to panic. There’s plenty of inventory of existing furnace models, which should make the transition smooth. Still, if your furnace is nearing the end of its life, it’s worth exploring replacement options soon. Early planning provides more flexibility and can help you secure the optimal combination of efficiency, comfort, and available incentives.
Keep in mind that rebate programs and federal incentives are subject to change over time, so replacing your furnace before 2026 may help you take advantage of existing offers. Our team at Save Home Heat Company will continue to share updates as policies, rebates, and inventories evolve, so you always have the latest information when making decisions about your home’s comfort system.
What’s Next for Denver–Boulder Metro Area Homeowners
While there’s no need to panic, it can be a good idea to plan ahead and know what’s coming down the pipeline. If you may need to replace your furnace in the next year or two, or you’re just looking to upgrade, our team at Save Home Heat Company is happy to help Denver–Boulder metro area homeowners find a solution that fits their needs.
If you’re wondering how the new ULN standards may impact your furnace options, we can talk you through the differences and help you make a choice that prioritizes your goals and capacity needs.
To learn more or receive a free, no-pressure quote, please contact our team today!
