What is Colorado's Model Low Energy and Carbon Code?

Thinking about a remodel or a new build in Colorado? The state now has a Model Low Energy and Carbon Code (MLECC) that raises the bar for comfort, indoor air quality, and long-term operating costs. It is not about making projects harder. It’s about making homes perform better, last longer, and cost less to run. The idea is simple. When your city or county next updates its building codes after July 1, 2026, it will need to adopt the MLECC or go stricter. That means future permits will check a few more energy and ventilation boxes than you may be used to.
Quick Answer: Colorado’s New Model Low Energy and Carbon Code: What You Need to Know
After local code updates on or after July 1, 2026, projects follow Colorado’s Model Low Energy and Carbon Code. Expect better comfort, healthier indoor air, and stronger efficiency with flexible compliance options and demand-response capable equipment.
Why Colorado Built This Code
In 2022, state lawmakers passed HB22-1362, which created an Energy Code Board to draft modern standards. The law directed the Board to publish the model code and set the adoption framework so local governments can use it the next time they refresh their building codes. The law set minimum energy code requirements while preserving local adoption. That creates more consistency across Colorado while keeping room for local choices.
What does that mean for you? When your city or county updates its building code after July 1, 2026, it must adopt the MLECC or adopt something that performs even better. You’ll see clearer expectations for insulation, air sealing, equipment efficiency, wiring readiness, and ventilation on plan sets and inspections.
What Changes for New Homes
Expect a practical checklist that nudges projects toward better envelopes and smarter equipment. Highlights you may encounter:
- Envelope quality: Tighter air sealing and right-sized insulation keep temperatures steadier and cut drafts.
- Heating and cooling options: Both all-electric and mixed-fuel designs can comply. The code offers clear compliance paths and credits that make high-efficiency electric heat and water heating straightforward to document
- Demand response capable systems: New construction must include heating, cooling, water heating, and lighting controls that are demand response capable where required. These systems can respond to a utility signal during peak demand and may qualify for utility programs.
Projects must meet the statewide model’s performance or prescriptive options set by the adopting jurisdiction. Check with your building department for any local amendments that apply to larger homes.
For many families, high-efficiency heat pumps are attractive because one system delivers heating and cooling and performs well in cold climates. That can mean steadier comfort and lower utility bills over time. This direction aligns with Colorado’s building decarbonization goals.
What Changes for Renovations, Additions, and ADUs
Not every small refresh triggers major upgrades, but additions and significant remodels will interact with the MLECC once your jurisdiction adopts it. Counties and cities will use the model when updating their codes, which apply to both new construction and certain renovation scopes. The exact thresholds for what is considered an “addition,” “alteration,” or “substantial improvement” are set in local code text, so it is important to clarify with your building department.
Two quick examples to make this real:
- Kitchen gut with new exterior openings: Likely triggers envelope details around new walls or windows, plus updated ventilation and right-sized equipment checks.
- Small bathroom refresh with fixtures only: Often, minimal energy code impacts, though local rules may still require ventilation or lighting updates.
If you are planning an ADU, budget time for envelope, ventilation, and electrical capacity planning. ADUs are small, which makes good air sealing and balanced ventilation especially important for comfort and indoor air quality. Homeowners should also verify panel capacity and plan for “electric-ready” needs.
The Upside for Homeowners
A better code should feel better to live with. Expect steadier temperatures, quieter equipment, cleaner indoor air, and lower utility costs over time.
- Comfort you can feel: Tighter shells and right-sized systems mean fewer hot and cold spots.
- Quieter operation: Modern high-efficiency systems often run more quietly.
- Healthier indoor air: Balanced ventilation and filtration reduce pollutants and help manage humidity.
- Lower utility costs over time: Efficiency gains cut energy use and 
utility costs, and demand-response capability can qualify for utility programs.
- Resilience: Homes that hold temperature better ride out outages and heat waves more gracefully.
- Future-ready value: Electric-ready wiring and efficient equipment position your home for future technology and market expectations.
Timeline and Who Must Adopt
Here is the timing that matters for planning:
- Now through June 30, 2026: If a city or county updates its 
current code in this window, it must adopt an energy code that is at least equivalent to the 2021 IECC and include electric-ready and solar-ready provisions developed by the Energy Code Board.
- Starting July 1, 2026: When a city or county next updates any of its building codes, it must adopt the Model Low Energy and Carbon Code or an equivalent that achieves equal or better energy and carbon performance. The MLECC becomes the new floor at the time of each local update. Your permit will follow whatever code is in force locally when you apply.
This staggered approach keeps projects moving while aiming for a consistent statewide performance level. Local adoption dates will not all be the same, so always check what is current in your jurisdiction.
Cost, Equipment, and Practical Planning
Upfront costs can shift depending on your starting point and project type. Many buyers offset new equipment or envelope measures with lower monthly utility bills and potential incentives. The code keeps compliance pathways flexible so builders can choose the mix that fits the design.
Before you design too far, line up the basics:
- Energy goals: Decide whether you want all-electric or mixed fuel. Both can comply.
- Panel capacity: Ask your electrician to assess headroom for heat pumps, heat pump water heaters, induction, and EV charging.
- Ventilation plan: Specify balanced ventilation with filtration. This is a comfort and health play as much as an energy one.
- Envelope check: Air sealing, insulation, and high-performance windows pay you back daily.
- Utility coordination: Explore demand response programs and rebates that match code-ready equipment.
Final Thoughts
The Model Low Energy and Carbon Code is about smarter homes and lower bills, not hoops for the sake of hoops. With a clear plan, you will get a house that feels better year-round, breathes better, and costs less to operate. When you are ready, let us talk about how a code-smart plan can shape your project so construction is smooth and the results are worth it.











