Between House Bill 23-1161 and the flurry of questions it’s stirred up, Colorado Springs homeowners have had plenty to sort through this year.
As of July 31, 2026, the ENERGY STAR efficiency requirement for gas furnaces in Colorado went up.
Gas heating isn’t going anywhere, and you’re not on the hook to replace a furnace that’s still doing its job. This update simply raises the bar for what a new furnace has to hit under one of the law’s two compliance paths.
Here’s what changed and what it actually means if you’re thinking of making a change to your furnace.
A Quick Recap on House Bill 23-1161
Since January 1, 2026, any new gas furnace installed in Colorado must meet one of two standards: ENERGY STAR certified or ultra-low NOₓ (ULN) compliant. Only one path is required and nothing in the law says you have to replace equipment that’s still running.
If you want the full picture of what the mandate covers and who it affects, our earlier post, Understanding Colorado’s 2026 Furnace Mandate: What It Is, What It Isn’t, & What to Do Next, walks through it in plain terms.
What Changed on July 31, 2026
ENERGY STAR is the EPA and DOE’s joint program for flagging high-efficiency equipment, and Colorado is part of its North region. From the start of the year through July 30, 2026, a gas furnace only needed to reach 95% AFUE (annual fuel utilization efficiency) to qualify under the ENERGY STAR path. On July 31, that number climbed to 97% AFUE.
That means any new furnace installed after July 31 going the ENERGY STAR route now needs to hit 97% efficiency instead of 95% to count as compliant.
Nothing about the Ultra-Low NOₓ path has shifted. A furnace can still meet the law by keeping nitrogen oxide emissions at or below 14 ng/J, completely separate from the AFUE requirement. If a system doesn’t clear the new 97% mark, ULN compliance is still very much a working option.
What This Means If You’re Replacing a Furnace
For homeowners shopping for a new furnace right now, the pool of ENERGY STAR-qualifying furnaces has shifted over towards higher-efficiency equipment.
But that’s not something to stress over. There are still a number of compliant systems available across a wide range of budgets and feature options.
If your existing furnace is still chugging along fine, this update changes nothing for you. You don’t need to touch a system that isn’t causing problems.
Peak Home Performance Keeps Up So You Don’t Have To
Between the original mandate and this AFUE increase, Colorado’s furnace rules have moved more than once in a single year. Our team at Peak Home Performance stays current on exactly what qualifies, whether you’re planning ahead for a replacement or dealing with a system that failed without warning. We proudly serve Colorado Springs, Monument, Pueblo, Woodland Park, and the rest of the Front Range with the same straightforward, upfront approach we’ve built our name on.
Call (719) 888-5705 or schedule online and we’ll help you sort out which systems meet the current standard. For more on what to do if your equipment has already failed, see Missed Colorado’s 2026 Furnace Deadline? Here’s What to Do Next.
This post is for general informational purposes and isn’t legal advice. For questions about how HB23-1161 applies to your specific situation, consult the official bill text or a licensed professional.
