The Denver City Council safety committee unanimously approved an ordinance Wednesday that would require all large commercial and multifamily buildings in the city to reduce greenhouse gas emissions and improve energy performance.

The ordinance now advances to the full council for two final votes in the coming weeks.

In Denver, commercial and multifamily buildings produce 49% of the city’s greenhouse gas emissions, according to the Office of Climate Action, Sustainability and Resiliency.

“We are not on track to achieve our climate goals of cutting building energy use 30% by 2030. Instead, building energy use continues to go up,” said Katrina Managan, who leads the office’s Buildings and Homes Team.

If passed, the ordinance would require buildings 25,000 square feet or larger to achieve 30% energy savings by 2030, with interim goals set in 2024 and 2027.

Buildings between 5,000 and 24,999 square feet would have to install all LED lights or use solar power to meet 20% of energy usage. Those deadlines range from December 2025 for larger buildings to December 2027 for smaller buildings.

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In addition, the ordinance would gradually require buildings to use electric heating systems when they replace existing gas systems.

In 2025, electric heat pumps would be required when easy to electrify systems need to be replaced (like furnaces, rooftop units and individual water heaters). In 2027, electric heat pumps would be required for harder to electrify systems as well (like PTACs, boilers and central hot water).

“This ordinance represents climate benefits that are huge and impressive,” said Christine Brinker with the Southwest Energy Efficiency Project. “This really makes Denver a leader and is something we can truly be proud of.”

The changes would reduce greenhouse gas emissions from Denver’s buildings by roughly 80% by 2040, according to the Southwest Energy Efficiency Project.

The ordinance would not influence single-family homes, but the city said it plans to launch outreach efforts to encourage homeowners to go electric.

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“It’s exciting,” said Councilman Jolon Clark. “I think it’s a perfect example of Denver at its best when we come together. … To have speaker after speaker come up from all different sides of this, and not one person in opposition.”

A potential argument against the ordinance is that the new requirements would strain Denver’s electric system. But the city said the system is already built to withstand high air conditioning during the summer, so the electric heating would not cause issues or require infrastructure buildout.

The ordinance seeks to prevent cost concerns by including exemptions for replacing gas heating systems with electric if electric would be significantly more expensive. In these cases, the city intends to cover the costs if the building applies for an economic hardship exemption.

Brinker said the city will also offer other forms of exemptions for buildings that struggle to meet the goals established in the ordinance.

“We built in flexibility at every single step,” Brinker said. “Buildings that can’t achieve their trajectory can request an alternative compliance pack, they can request a different compliance timeline, they can request an adjustment to their end goal.”

Buildings that fail to comply with the ordinance would pay fees slightly higher than the cost of compliance, the city said.