Columbia Adopts the 2024 Energy Code: What It Means If You're Building in 2027

On September 21, 2026, the Columbia City Council adopted the 2024 International Energy Conservation Code (IECC), replacing the 2018 version the city has used since 2019. The new code takes effect April 1, 2027 and applies to new construction, not to existing homes.

If you're planning to build in Columbia, or you're just outside city limits and want a home that holds its value, here's what you need to know.

What changed

• Columbia moves from the 2018 IECC to the 2024 IECC. That is a jump of two code cycles.
• Council passed local amendments covering renewable energy systems, load management, and duct testing. Amendments to the thermal envelope, ventilation, and lighting rules failed.
• There is still no statewide code. Missouri leaves residential energy codes to each city and county, so rules in Ashland, Hallsville, or unincorporated Boone County can differ from Columbia's.

What it costs and what it saves

KOMU reported a city estimate of $8,000 to $12,000 in added construction cost for a typical single-family home. Council also heard a lower estimate of $3,000 to $4,200. The projected savings were about $125 a year for an 1,800 sq ft all-electric home.

Those savings were calculated at today's rates. Rates are not standing still: Columbia Water & Light raised electric usage charges 6% this October, and Ameren Missouri has a new rate case pending. (See our Mid-Missouri rate update.)

Code is the minimum, not the goal

An energy code sets the floor. If you're already pouring footings and framing walls, the cheapest time to build a tight, efficient, resilient house is now, not after the drywall is up. In practice, that means:

1. The envelope first. Continuous insulation and airtight walls, such as insulated concrete forms (ICF), cut heating and cooling loads for the life of the home.
2. Efficient, all-electric heating and cooling. A geothermal heat pump uses the steady temperature of the ground, and DOE says it can cut heating and cooling energy use by 30–60%.
3. Solar-ready (or solar-installed) from day one. Plan roof orientation or a ground-mount location, conduit runs, and panel capacity during design.
4. Battery-ready electrical. A critical-loads panel costs far less to plan now than to retrofit later.

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Building checklist for 2027

• Ask your builder which code edition your permit will fall under (permits applied for before vs. after April 1, 2027).
• Get a blower-door and duct-leakage test plan in writing.
• Size solar from the home's modeled usage, not a guess.
• Decide early on geothermal. Loop fields go in before landscaping.

Talk to us before you break ground

Solar Sam is based in Columbia, MO, and works with Central Missouri homeowners and builders to plan solar, battery backup, and energy-smart design from the blueprint stage. Call (573) 819-9623 to talk through your plans.

Sources: City of Columbia Legistar B241-26; KOMU 8; Missouri DNR. This is general information, not legal or code-compliance advice. Confirm requirements with the City of Columbia Building & Site Development office.