Planning a home project in Boulder

Boulder plays by its own rulebook. The city writes local amendments into nearly every code it adopts, it set climate goals that reach into how houses are built and remodeled, and it sits against the foothills and along Boulder Creek, so wildfire and flood rules both apply in places. Housing ranges from 1880s-1910s houses in Mapleton Hill and Whittier to postwar ranches in Martin Acres and Table Mesa, 1970s-80s homes in north Boulder and Gunbarrel, and newer infill.

The upside of all that regulation is clarity. The city publishes detailed guides, and if you read them before you design, you'll avoid most surprises.

Boulder's own energy code

All projects in the city must be designed to the 2024 ICC codes and the 2024 City of Boulder Energy Conservation Code, which took effect on December 1, 2024. The city's goal is to move all building types toward net-zero, outcome-verified codes by 2031. For existing homes, the most important points are:

• The code applies to renovated buildings, not just new ones, so additions and major remodels pick up energy requirements.
• The city's energy code page says new work must not rely on fossil fuel for space and water heating, cooking or fireplaces in covered projects. If your remodel replaces a furnace or water heater as part of a permitted scope, expect to plan for electric equipment, typically heat pumps. Ask the city early how the rule applies to your exact scope.
• Energy Rating Index (ERI) scores, similar to HERS scores, are used for some compliance paths. On that scale, 100 equals a 2006 energy-code home and 0 is net-zero.

In practice, that makes Boulder the metro's most natural place for a cold-climate heat pump, a heat pump water heater, better windows and air sealing.

Rebates for Boulder County households

EnergySmart, the Boulder County program, offers income-qualified rebates of up to $2,000 toward heat pumps, electric water heaters, insulation, induction stoves and other upgrades, funded by the county's sustainability tax. Eligibility depends on household income, and pre-approval is required, so check current terms before you sign a contract. Xcel Energy rebates may also apply.

Wildfire code on the west side

Boulder first adopted the International Wildland Urban Interface Code in 2014 and has updated it on a six-year cycle. The city recently adopted the 2024 edition with local amendments, and its requirements apply to building permits for properties in the mapped WUI area as of August 1, 2025. Check the city's WUI map for your address.

Roofing gets close attention. Boulder's roof inspection guide says inspectors may ask for Class A listed-assembly documentation and wind design information, and it requires a mid-roof inspection when the pitch is less than 4/12 or the roof is anything other than asphalt shingles. Make sure your roofer knows the inspection schedule. Missing it is expensive.

Historic districts and landmarks

Boulder has a number of designated historic districts and individual landmarks. For a designated property, exterior changes generally need a Landmark Alteration Certificate (LAC) before the building permit. The city says applications approved at the staff or Landmarks Design Review Committee level in one round take between 2 to 4 weeks, with 2 to 3 more weeks for each additional round. Applications that go to the Landmarks Board take between 6 weeks and 3 months. Window, door, porch, dormer and addition applications need detailed drawings and product information.

Floodplain

If any part of the structure or the proposed work is in the 100-year floodplain, Boulder requires a floodplain development permit. Many routine projects are reviewed along with the building permit, but substantial work in high-hazard areas has its own process. Look up your property on the city's floodplain maps before you design an addition or finish a basement near a creek.

Rentals: SmartRegs

If you rent out a Boulder house or ADU long-term, it needs a rental license and must meet SmartRegs, the city's energy-efficiency standard for rentals. Upgrades such as insulation, air sealing, windows and heating systems are typical ways owners earn compliance points. Plan those upgrades together with any remodel so you're not opening walls twice.

Projects that make sense here

• Heat pumps and electrification, which line up with the city's code direction and rebate programs.
• Windows and insulation in older homes, with LAC review for street-facing windows on designated properties.
• Roofing with Class A assemblies and the right inspection plan.
• Basement finishing, where floodplain rules and radon testing come first.
• Additions, designed with an eye on energy code and, in historic districts, landmark review.