2025 Denver Energy Code - Key Commercial Amendments

Simplifies compliance for new and replacement space heating and water heating equipment for additions and alterations

Now only new buildings, not new equipment in existing buildings or additions, are prohibited from using

• Fossil-fuel furnaces
• Electric resistance space heat
• Or fossil-fuel and electric resistance water heaters

with exceptions.

Simplifies required submittals when gas equipment is used in additions and alterations

C403.2.4

C404.10

C503.3.2

C503.3.3

C503.4.1

Water heating equipment location requirements to accommodate future heat pump equipment does not apply if using a boiler

• Equipment location requirements are now limited to fossil fuel water heaters less than 200,000 Btu/hr (under the threshold for boilers) and is aligned with the capacity in C404.10 Exception 10 which allows gas boilers

C404.12

Aligns with State Model Low Energy and Carbon Code for additional electric infrastructure for new buildings and first tenant finish

• Additional electric infrastructure requirements are based on a new term combustion equipment which includes more equipment types than 2022 DEC
• Now required for fossil fuel water heaters less than 200,000 Btu/hr (under the threshold for boilers) and is aligned with the capacity in C404.10 Exception 10 which allows gas boilers
• Clarifies electrical system requirements

C405.15

Updates to Change of Occupancy or Use (in 2025 Denver Energy Code 2nd Printing)

• New exemption for small spaces less than 5,000 sf
• Updated Energy-Demand Category table 

Clarifies when additional energy efficiency credits are used

• Updates when new buildings and additions use additional energy efficiency credits and the total credits required

C406.1

C502.3.7

New defined term for first tenant finish

Uses first tenant finish(es) for the first-time build out of any spaces in a core and shell building and clarifies the requirements for water heating equipment location, electric infrastructure, and additional energy credits

C202

C404.12

C405.15

C406.1.1

Aligns with CO Model Electric Ready and Solar Ready Code for electric vehicles (EV)

Simplifies EV requirements and categories

C405.13

Aligns with CO Model Electric Ready and Solar Ready Code for solar access and solar-ready zone

• Applies to new buildings (removes reference to occupancy groups)
• Consolidates requirements (removes Appendix CB)
• Clarifies electrical service reserved space

C405.14

Aligns with CO Model Low Energy and Carbon Code for new defined terms

• Combustion equipment
• Core and shell, first tenant finish
• EV capable space, EVMS, new parking facility, parking facility
• Future electric equipment

C202