What the state law addresses
As checked October 6, 2026, Colorado's statute addresses manufacturing, distribution, sale, offers for sale, and leasing of covered new equipment beginning January 1, 2026. It sets a furnace NOx emissions limit and provides an ENERGY STAR compliance route. It does not state that every previously installed household furnace must be replaced. That last distinction is our reading of the new-product scope. HB23-1161 signed law, sections 25-7-1503 and 1504.
NOx refers to nitrogen oxides produced by combustion. This is a different question from whether a particular furnace has a failed part or is operating safely. An emissions sales requirement cannot establish a defect in your existing furnace.
The current exceptions matter
The 2026 signed amendment adds exemptions until January 1, 2031 for propane-fueled products and for equipment designed and listed exclusively for manufactured homes when installed as a replacement in a manufactured home. The act's ordinary effective-date provision identifies August 12, 2026, subject to its referendum condition. The manufactured-home exception is specific, not an exemption for every heater in any manufactured home. SB26-002 signed act, pages 12-15.
Do not rely on a contractor handout written before that amendment to settle a current purchase. Have the applicable authority or a qualified compliance reviewer confirm the exact model, fuel, use, and any exemption.
Does this mean a future replacement has no requirements?
No. An existing furnace and a new replacement purchase are different questions. If you choose or need replacement, ask for the proposed full model number, the documented compliance basis, and the installation requirements for your jurisdiction. Permit and code questions still need address-specific confirmation.
We recommend keeping the choices visible: continued use supported by a qualified condition assessment, an appropriate repair if needed, and a compliant replacement if the findings or your plans justify it. A rule affecting new products does not make a working existing unit defective.
What to ask before signing
If someone says “the law requires you to replace this now,” ask for the law's section, effective date, and how it applies to an already-installed furnace. Ask whether the recommendation actually rests on a safety finding, a needed repair, or restrictions on the new equipment they can supply.
A qualified technical reviewer should assess the furnace's condition. The relevant building authority, state agency, or legal professional can clarify a disputed legal obligation. Those are different roles.
The next step is to request the precise requirement and the written equipment finding separately. Decide from those two records, rather than from a broad claim that Colorado has banned every existing gas furnace.