City vs County Energy Codes: Plan Your Remodel

Planning a remodel in Boulder and wondering if city or county rules apply to you? The answer can change your design, budget, and timeline. Energy codes in the City of Boulder and unincorporated Boulder County look similar at first glance, but the triggers and requirements differ in important ways. In this guide, you will learn how to identify your jurisdiction, what work triggers stricter energy rules, and the simple steps to plan with confidence. Let’s dive in.

Know your jurisdiction first

Before you sketch plans, confirm who enforces your permit. Colorado allows local governments to adopt their own energy codes, so rules change at the city line. The City of Boulder and unincorporated Boulder County each set and enforce their own requirements, and they update them on their own schedules. For state context on how local codes fit into Colorado policy, review the ACEEE overview of Colorado’s energy code framework.

Inside city limits, the 2024 City of Boulder Energy Conservation Code is active for permits filed after Dec. 1, 2024. You can review current provisions on the city’s Energy Conservation Code page. Properties outside city limits but still in the county follow Boulder County BuildSmart and related county code amendments.

City vs. county: what changes for your remodel

City of Boulder at a glance

• The 2024 CoBECC sets an all-electric expectation for new residential construction and additions. Qualifying substantial remodels also need electric space and water heating, with limited exceptions.
• Larger additions and major alterations can trigger performance modeling. Additions over 1,000 square feet must use the ERI path. The city’s energy code FAQs explain how levels of alteration are classified and how combined projects are handled.
• The city maintains both prescriptive and performance paths, with tightened ERI targets for residential projects.

Boulder County (unincorporated) at a glance

• BuildSmart drives energy performance using HERS ratings and offers multiple compliance paths. The largest new homes must meet zero net energy outcomes. Explore the county’s BuildSmart overview and the Zero Net Energy page.
• County code amendments effective March 31, 2025 incorporated electric-ready and solar-ready requirements. See the county’s Building Code Amendments for details.
• Remodels and additions often require BuildSmart documentation at permit submittal. County reviewers will confirm the compliance path for your scope.

What triggers stricter requirements

Additions and major alterations in the City of Boulder

• Level 3 alterations, generally work exceeding 50 percent of the building area, plus replacement of major mechanical systems and significant envelope work, are considered substantial. These projects trigger electrification and performance compliance.
• Additions over 1,000 square feet must follow the ERI path. If your project combines an addition and an alteration, the larger scope typically governs.

New builds and additions in unincorporated Boulder County

• BuildSmart applies to new residential construction and additions. Many projects use HERS ratings to show compliance.
• The county will identify whether your remodel requires a HERS report or prescriptive measures when you submit for permits.

Electrification, solar, and EV readiness

Inside the City of Boulder

If you are building a new home, adding onto an existing one, or completing a qualifying substantial remodel, plan for electric space heating, a heat pump water heater, and electric cooking unless you qualify for a narrow exception. The code also includes an envelope backstop that protects overall efficiency. Find current rules on the city’s Energy Conservation Code page.

In unincorporated Boulder County

The county emphasizes performance through BuildSmart and requires electric-ready and solar-ready provisions under the March 2025 amendments. The largest new homes must reach zero net energy outcomes. Expect to plan for panel capacity, dedicated circuits, and pathway space for future electrification, plus roof and electrical planning for solar.

Step-by-step remodel planning checklist

1. Confirm jurisdiction and permitting authority

• Use local parcel tools or contact the applicable building office to confirm whether your property is in the City of Boulder or unincorporated Boulder County. Start here if you are unsure: Boulder County building permits.

2. Define your project scope

• Classify the work as a repair, Level 1, Level 2, Level 3, or an addition. In the city, Level 3 or substantial alterations and additions over 1,000 square feet trigger stricter compliance. See the city’s energy code FAQs for definitions.

3. Engage the right experts early

• Many paths require an energy model. Hire a RESNET HERS rater or ERI professional for residential projects. The county outlines HERS details here: Home Energy Rating for Boulder County.

4. Talk to your utility before finalizing solar

• Contact Xcel Energy early to confirm interconnection rules and any program requirements. Start with Xcel’s recovery and rebuild resources if your project ties to a rebuild program.

5. Plan for electrification or electric-ready

• Inside the city, expect all-electric systems for new homes, additions, and substantial remodels. In the county, expect electric-ready and solar-ready provisions plus HERS compliance. Budget for a panel upgrade and EV-capable circuits if needed.

6. Check incentives and timing

• Incentives often require early registration at or before permit submittal. Explore current programs through the RebuildingBetter incentives hub.

7. Prepare complete permit documents

• Typical submittals include full plans, energy compliance checklists, preliminary HERS or ERI reports, and equipment specs. The city posts required materials on the Energy Conservation Code page.

8. Choose experienced contractors

• Select HVAC, electrical, and solar contractors who have delivered projects under CoBECC or BuildSmart. Ask for examples of successful compliance.

9. Expect verification at the end

• Your project will include inspections and final verification. Be ready to submit the final registered HERS or ERI documentation if your path requires it.

Quick scenarios to make it real

East Boulder addition, 1,200 square feet

You plan to expand a kitchen and add a primary suite inside city limits. Because the addition is over 1,000 square feet, you will follow the ERI path and plan for all-electric space and water heating. An early energy model helps align insulation, window choices, and mechanicals with the target.

Home just outside city limits, modest remodel with a 500-square-foot addition

Your property is in unincorporated Boulder County. BuildSmart applies, and you will likely show compliance through a HERS path. The county requires electric-ready and solar-ready provisions. You keep the scope modest and avoid triggering city-style all-electric requirements because you are outside city limits.

When to bring in pros

• An energy rater can run your ERI or HERS model before you finalize design, which reduces change orders and surprises at plan review.
• An experienced HVAC contractor can confirm heating and cooling loads and select heat pumps sized for our climate.
• Your electrician can evaluate panel capacity early and plan EV-capable circuits and solar-ready conduit while walls are open.

Planning a remodel is simpler when you know the rules and build your team early. If you want a second set of eyes on scope, value, and compliance strategy, reach out to John Canova for renovation-savvy real estate guidance.

FAQs

Do City of Boulder rules require me to remove existing gas appliances?

• No. Existing gas appliances typically do not need to be removed right away. The city’s rules apply to new construction, additions, and qualifying substantial remodels. See the city’s energy code FAQs for details.

What work triggers electrification in Boulder vs. the county?

• In the City of Boulder, additions and substantial remodels trigger electrification requirements and performance paths. In unincorporated Boulder County, BuildSmart focuses on energy performance and electric-ready provisions rather than a blanket all-electric mandate.

Do additions always require energy modeling?

• In the City of Boulder, additions over 1,000 square feet require the ERI path. In the county, many projects follow a HERS path. Your plans examiner will confirm the exact path based on your scope.

How do I capture available incentives for high-efficiency upgrades?

• Register early since some programs require enrollment at or before permit submittal. The RebuildingBetter incentives hub maintains current options for heat pumps, heat pump water heaters, and solar.