In 1981, state lawmakers passed a statewide ban on local rent control policies. The history of the prohibition was a response to a pro-tenant movement in Boulder. Credit: John Herrick

The coldest temperature this winter at the new home of Joe Smyth and Kristen Taddonio was 17 below. They live in Fraser, a Colorado town that used to get far, far colder.

Still, that February night was cold enough to test the design and technologies employed in construction of the couple’s 1,176-square-foot house. Even after charging their electric car, their house produces more energy than it consumes.

An air-source heat pump was central to their mission in creating a net-zero home, one gutted of emissions from fossil fuels. It extracts heat from outside – even on chilly nights – to warm the interior. 

The Mitsubishi model used at the Fraser house promises to deliver the necessary indoor heat, even when outside temperatures dip to 13 below. To supplement the air-source heat pump should temperatures dive to 30 below, as was once common, the couple also installed electrical-resistance heating. 

Colorado needs many more air-source heat pumps — and fewer carbon emissions from buildings — to meet its mid-century decarbonization target goals of 90%.

Getting this right during housing construction costs less in the not-very-long term. Building permits for 48,200 housing units, both single-family and multi-family, were issued last year, according to the Colorado Business Economic Outlook. That’s like adding a new Greeley each year, along with a few small towns. 

Retrofitting our older buildings is laborious and expensive. 

But several bills working their way through the Colorado Legislature this spring would nudge Coloradans in that direction, toward low- and no-carbon technologies. All cost more upfront, but save money over time – sometimes lots of it – while reducing or eliminating emissions. 

Incentives for heat pumps, energy storage and low-carbon building materials

Carrots would be offered by SB22-0151 to those who purchase air- and ground-source heat pumps. Purchasers would be allowed income-tax exemptions of up to 10% of the purchase price.

Other provisions in the bill approved by the House Energy and Environment Committee offer tax incentives for energy storage and building materials with low levels of embodied carbon. 

Christine Brinker, representing the Southwest Energy Efficiency Project, testified that her family’s air-source heat pump paid for itself in six years because of lower energy costs. Air-source heat pumps help residents of Geos, a net-zero neighborhood project in Arvada, to pay as little as $6 a month in energy costs.

“It is just more efficient to move heat than to create heat,” said Rep. Mike Weissman, a Democrat from Louisville and a bill supporter. “I think we can do some good here by amending that pay-off time curve just a little bit. That’s something that we need to do to facilitate our transition” from fossil fuels.

Air-source heat pumps can also move heat from inside buildings during summer, effectively becoming air conditioners. 

Statewide mandate to adopt 2021 IECC building code, with Louisville representative a sponsor

The second bill, HB-1362, would require towns, cities and counties to adopt the 2021 International Energy Conservation Code (IECC) before 2025. This latest code advances efficiency 8% to 9%, compared to the 2018 iteration. 

Natural gas will still be allowed, but air-source heat pumps more efficiently meet the 2021 code’s elevated standards. 

The Colorado Municipal League objected to loss of local control. Two representatives of rural areas described it as onerous for small towns despite $3 million earmarked for training. Homebuilders argued that the advanced standards would make already expensive housing less affordable. 

Howard Geller, also representing the Southwest Energy Efficiency Project, cited a study from the Pacific Northwest National Laboratory that found the latest code would indeed add $200 to the cost of an average mortgage in Colorado built to this latest code. Lower energy costs will more than recoup that extra cost, he said, even in the first year.

Rep. Tracey Bernett, a Democrat from Longmont whose district includes Louisville and nearly half the 1,084 homes destroyed by the Marshall Fire, said she sponsored the bill with full confidence it will help, not harm, her constituents. Both the City of Louisville and Town of Superior are allowing Marshall Fire victims who are rebuilding their homes to be exempt from following the 2021 IECC code – which is already locally mandated there –  and to instead follow the less-stringent 2018 IECC code.

Bennett said the state legislation would override local building codes, including the  exemptions for fire victims. But the mandate would not be required until 2025 — and only on new construction and major remodels.

These bills both moved from the House committee on strictly party-line votes, with Democrats in support. 

A third bill, HB22-1381, has bipartisan sponsors — and bipartisan support. It would allocate $20 million for grants to further geothermal energy, which taps the year-round heat of 55 degrees found 8 to 10 feet below the surface for electricity.

As with air-source heat pumps, sponsors said the market needs to be nudged to adopt technology that costs more upfront than installing natural gas infrastructure but pays off in the long term. “This is something we don’t do enough of,” said Rep. Hugh McKean, a Republican from Loveland, who is installing geothermal in a house he is constructing.

McKean isn’t the only Republican supporting the legislation. Citing the experience of family members with the technology, Rep. Perry Will of New Castle is also throwing his weight behind the measure. 

“I really like this bill,” he said.

This article was published as part of a collaboration between the Boulder Reporting Lab and Big Pivots, a nonprofit that covers energy and other transitions in Colorado and beyond, made necessary by climate change. Big Pivots is published by Allen Best. Subscribe for free at