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Photo of the ashes in Louisville days after the Marshall Fire. Photo/Robert Castellino Photography

Boulder County city wrestles with whether to stay the course on building with the future in mind


by Allen Best

A remarkable discussion has been underway since the Marshall Fire in Boulder County about how to rebuild.

The conversation has seesawed on the question of costs, the short term vs. the long term. Really, the question revolves around the viability and cost-effectiveness of existing building technology that does not rely directly upon fossil fuels.

Colorado has been having this conversation quietly in small circles for over a decade: the GEOS project in Arvada, the Westminster residence whose owner several years ago stubbed his natural gas line; and the two lower-income housing projects in Basalt that have no natural gas.

Last year, Colorado legislators began nudging the conversation along with new laws that tilt the table, some would say level the field, to recognize the long-term costs of natural gas use in homes. More legislation is being considered that is explained later in this issue.

The Marshall Fire had put some of these same questions about costs and change front and center.

Louisville, being among Colorado’s most progressive municipalities, had adopted the 2021 iteration of the International Energy Conservation Code. This code represents a 9% gain in energy efficiency over the code adopted in 2018.

Building codes in the 21st century have become ever-more attentive to energy efficiency. The 2018 code represents a 51% gain over the last few decades, including the codes which houses were required to meet in the early 1990s, when most of the 1,000 homes lost in the Marshall Fire were constructed.

The newest code also envisions a future in which electricity will displace some existing uses of fossil fuels, requiring higher standards of wiring for charging electric vehicles and air-source heat pumps. That extra wiring does bump up the costs.

At issue is the cost of building to this latest code vs. the 2018 code. That is relevant in that many of the homes lost in the fire were underinsured.

Superior decided that those rebuilding need only meet the 2018 code. A majority of city council members in Louisville, in a meeting this past week, indicated that they also intend to allow those who lost homes to revert back to the older code.

Just how much more would it cost to build to the 2021 code? City officials sought the aid of builders, and others. The estimates range widely, between $5,000 and $75,000. The lowest cost estimate comes from the Southwest Energy Efficiency Project, and the latter for a 2,400-square-foot house by the Home Builders Association of Metro Denver.

The city staff report settled on an estimate of $20,000.

As reported by the Boulder Reporting Lab, some at last week’s meeting of the Louisville City Council said they want to be sustainable—but it just costs too much. Others, including at least one council member who lost her home, want to stay the course with the 2021 code. That homeless council member, Deborah Fahey, said she believes the incentives and rebates will cover the added cost.

Those incentives are remarkable. Xcel Energy offers one-time incentives ranging from $10,000 to $37,500, the latter built to Passive House standards. A solar developer, SunShare, quickly engineered plans to dedicate a 5-megawatt community solar garden for use of those rebuilding. This allows homebuilders to lower their scores of HERS, a rating system designed to reflect emissions. The lower the rating, the fewer the emissions. This would replace the higher cost of on-roof solar.

State Rep. Tracey Bernett, whose district includes Louisville, believes that building back with reduced emissions won’t be that difficult. “You have to know how to do it, but it’s not necessarily any more expensive,” she says citing the consultations with green builders, including testimony last week to the Louisville City Council.

One option in building back is to eliminate natural gas hook-ups. Air-source heat pump technology has arrived. It’s more expensive than a natural gas furnace, but the fuel—electricity, derived increasingly from renewable sources—will be much cheaper over the long haul.

Also interesting is how the social cost of carbon has entered such discussions. All electric technology will within a few years largely displace fossil fuels from homes as the electric grid becomes much more dependent on renewables. Looking at continued burning of natural gas through the lens of the social cost of carbon would add $3,210 over 15 years to a home burning natural gas.

Beyond the social cost of carbon, there is the cost of carbon itself. Natural gas has been cheap for more than a decade, but prices have been rising. There are no assurances they will drop again.

“The thing that gets lost in the conversation is if you are not dependent upon natural gas, that really affects your long-term energy costs,” says Bernett.

That was also the testimony last week of Andrew Michler principal of Hyperlocal Workshop, a design firm in Colorado dedicated to Passive House construction, the type that milks energy out of the sun. His bottom-line message in a 90-minute workshop last week sponsored by the Colorado Renewable Energy Society is that it need not cost more, but you do have to think harder.

“Production builders have pretty much fought all code improvements in my experience over the last 25 years,” he said. Building codes are minimums—not what can be done, he emphasized, although maximizing benefits does require rigorous thinking.

The irony of the Boulder County discussion is that this wildfire that consumed more than 1,000 houses did have something to do with climate change. It was admittedly at the edges, hard to pick out from the confluence of events that resulted in a fire-ripe environment in December. That shifting climate is a major reason for these advances in technology, for the revised building codes.

Allen Best
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