Denver’s Green Buildings Ordinance offers benefits not only to building owners who can save on energy expenses, but also to contractors engaged in energy efficiency consulting and solar power installation who gain new business opportunities. Plant suppliers, landscape designers and installers can also benefit from the ordinance when building owners choose to comply with the ordinance by installing green roofs and green space. 

Passed by the City Council of Denver, Colo. in 2018, the ordinance seeks to achieve important environmental benefits for the city, primarily by reducing urban heat-island impacts and greenhouse gas emissions, said Amber Wood, Energy Program Administrator for the City of Denver’s Office of Climate Action, Sustainability, and Resiliency. 

Other U.S. cities that have enacted green buildings laws include Chicago, Ill., Devens, Mass., Fife, Wash., Seattle, Wash., New York City, N.Y., Portland, Ore., San Francisco, Calif., and Washington, D.C.  

Denver’s ordinance requires all new buildings and additions that are 25,000 square feet or larger to install a cool roof and select an additional compliance option. Existing buildings, 25,000 square feet or larger, must also comply when they apply for roof permits. The ordinance does not apply to parking structures, temporary buildings, air-supported structures, greenhouses, single-family homes, duplexes, or certain exempted residential buildings.

A cool roof is defined as using materials that meet specific solar reflectance values. Acceptable alternatives to the cool roof requirement include green roof areas, areas with solar systems or components, above-roof decks or walkways, HVAC systems and components, swimming pools, sport surfaces, and glazing.

The additional compliance options include: green roofs, green space, solar or other renewable energy, energy efficiency measures, green building certifications, a Green Building Fund payment, and Energy Program participation. 

From November 2018 to April 2021, 117 building or roofing projects were required to select a compliance option. Of these, slightly less than a quarter (23%) selected to install a green space or green roof.

Of the new buildings required to comply, 10 projects installed on-site green space, all at ground level, and three projects installed ground-level green space plus on-site solar. Of the remaining 10 projects that chose green space and energy efficiency upgrades, seven installed ground-level green space and three installed vegetated roofs.

Of the existing buildings required to comply, three projects installed on-site green space at ground level and one installed a vegetated roof.

According to a 2018 case study in Kansas City, Missouri by the U.S. Environmental Protection Agency, “integrating nature-based solutions like green roofs into the urban landscape can benefit the environment, public health, and society by: reducing stormwater runoff, lowering ambient air and surface temperatures, reducing the urban heat-island effect, increasing building efficiency, reducing energy use for heating and cooling, reducing air pollution, achieving health benefits, and improving psychological well-being through access to nature.

With the current construction and real estate booms in Denver, the number of buildings required to comply with the ordinance is growing daily. The inventory of existing buildings that will be required to comply when their aging roofs need replacing is large in itself. According to city statistics, Denver has 3,000 existing buildings that are more than 25,000 square feet, of which an estimated 75 to 300 buildings will require a roof permit each year, triggering ordinance compliance. That’s a healthy market that could be sold on installing green spaces and green roofs to meet ordinance requirements.

“The green industry can support the program through providing additional detail and education to their customers,” said Wood. “Please help us inform the community about the various compliance options available to add green space. You can find additional detail on Denver’s Green Buildings Ordinance webpage, including webinars, PowerPoint presentations, and a summary sheet.”

She also encourages CNGA members to reach out with questions to “We want to assist and promote the benefits of additional green space within Denver including the environmental and aesthetic benefits from more green space that our community can enjoy,” she concluded.