How Boulder is warming up to cold climate heat pumps

Heat pump installations in Boulder County tripled in 2023 compared to 2022. With more Boulderites shifting away from gas heating, the question remains: Can current heat pump technology handle sub-zero cold snaps on the Front Range?

Xcel Energy has said gas heating is still necessary during the state’s severe cold spells. Yet a growing community of electrification experts in and around Boulder disputes this claim and is helping residents make the switch. 

“The technology is capable of doing what we need it to do. Period,” said Shawn LeMons, a former Mitsubishi heat pump representative and current adviser for Go Electric Colorado, a group of Boulderites helping residents electrify homes and cars. 

Heat pumps operate as two-way air conditioners. In summer, they take warm air from inside and expel it outside. In winter, they collect warm air from outside and bring it in. This works as long as there is warm air outside, which there always is unless it reaches absolute zero on the Kelvin scale. Heat pumps are considered a climate solution because they run on electricity, which in Colorado is expected to be emissions-free by 2050. They’re also more efficient than gas furnaces in properly insulated homes.

Colorado’s winter cold snaps perpetuate the misconception that heat pumps are ineffective, experts say. As temperatures drop, heat pumps must work harder to find warm air to bring in. This leads to the belief that they can’t operate on their own on freezing nights. While many standard heat pumps may struggle in extreme cold, a small number of cold climate models are designed to function in temperatures as low as -25 degrees Fahrenheit.

“The technology is out there, you just need to know how to look, ” said Stuart Cummings, one of Go Electric Colorado’s founders. 

The Boulder-based nonprofit launched in October 2023 to help residents navigate the heat pump market and coordinate with contractors for installations. In its first few months, it has helped more than 100 households through the electrification process, with most of them in Boulder County. The organization’s reach already extends to Colorado Springs and Gunnison. Many of Go Electric’s volunteers have electrified their own homes, a process that taught them what works and what doesn’t.

“Our motto could be, ‘We experiment so you don’t have to,’” Cummings said.

One hurdle Go Electric Colorado frequently encounters is that many HVAC companies don’t yet trust heat pump technology, resulting in recommendations against installation or improper setups.

“If you get 10 quotes for a heat pump, eight of them won’t do accurate measurements of your heating load, and half of them will say heat pumps don’t work here,” Eric Stonebraker, a member of the tech team at Go Electric Colorado, said.

Cummings highlighted a concern with incorrect installations in rebuilds in the Marshall Fire burn scar. In one such rebuild, despite a state-of-the-art design and excellent insulation (referred to as the “envelope”), a heat pump with three times the heating capacity needed was installed, undercutting energy savings, Cummings said. “This house could literally warm two other homes.” 

Conversely, when a heat pump is too small it can fail to heat a home. But even with the right-sized machine, poor installation can lead to high electric bills. Some heat pumps have an auxiliary heat backup mechanism for colder nights. And Go Electric volunteers often encounter instances where the auxiliary heat is set to kick on at 32 degrees Fahrenheit, despite the heat pump’s capability to handle much colder temperatures. Cummings said the auxiliary heat mechanism can be 10 times less efficient than the heat pump itself.

LeMons, the former Mitsubishi rep, echoed Go Electric’s concerns. Finding a true cold climate heat pump amid the vast heat pump market that consists of “tens of thousands of pieces of equipment” requires a trained eye, he said. Even then, engineers from heat pump manufacturers tend to be conservative. For instance, although a Mitsubishi Hyper Heat, part of the brand’s cold climate line, can function down to nearly -25 degrees Fahrenheit, its official rating is only to -13 degrees, causing anxiety among homeowners and contractors.

LeMons said one way to navigate this conundrum is to work with a contractor who is enthusiastic about heat pumps. “If you have a Ford, take it to a Ford mechanic,” he offered as an analogy.

He cited Elephant Energy as an example, a local all-electric company he worked with while a rep for Mitsubishi. Go Electric Colorado volunteers also brought up Elephant Energy independently in an interview with Boulder Reporting Lab.

Elephant Energy is trying to offer homeowners the smoothest path possible to electrifying their life, according to DR Richardson, a Boulderite and co-founder of Elephant Energy. “We’re making it really easy for homeowners to upgrade their home and make it more climate friendly,” he said.  

In 2021, Richardson tried to get a heat pump for his home. After talking to 20 different contractors, “all but one said we could not put in a heat pump without gas backup.” So Richardson decided to form a company that would make the process easier. 

Elephant Energy has completed almost 40% of rebate-eligible HVAC projects in Boulder County since 2022. Its market share is even more significant among electric-only contractors.

“Up until a few years ago, heat pump technology was not robust enough for super cold weather conditions,”  Elephant Energy’s website says. “Technology improvements have now rendered this belief a myth.”

In addition to heat pumps, Elephant Energy also helps homeowners get heat pump water heaters, induction stove wiring, EV charging and insulation work. 

A few years into the business, Richardson said he is even more confident in the ability of heat pumps to handle Colorado’s climate, because he has tested them. Monitors placed in homes with Elephant Energy-installed heat pumps have shown consistent heating performance even during the coldest snaps of recent winters, he said. Elephant Energy mostly installs Mitsubishis, as well as Daikin and Bosch machines, along with a couple other brands.

“Cold climates are hard, and what we’ve found is Mitsubishi has some of the best cold weather performance,” he said.

Go Electric also mentioned the Mitsubishi hyper heat line, the company’s cold climate machines, but provided a caveat. “There are Mitsubishis that would perform poorly in this climate,” Stonebraker of Go Electric said. “Even within a brand, there are a lot of checks you do to make sure a heat pump would work here,” including examining its cold weather rating buried in the machine’s spec sheet. Those checks could be done for free, Stonebraker and Cummings said, by volunteers at Go Electric Colorado.

According to Rachael Bramblett, the lead residential advisor with Energy Smart, Boulder County’s residential sustainability program, Go Electric’s volunteers have built a valuable knowledge base.

“If they are looking to get technical solutions for heat pumps I would point them to Go Electric Colorado,” Bramblett said of Boulder residents interested in getting a heat pump. “Where Energy Smart can help is navigating the complex rebate landscape.”

Go Electric Colorado has a form on its website for residents to sign up for a free one-hour virtual consultation. Cummings said that even over a screen, Go Electric can give residents an idea of where to start. Often, that begins with an energy audit or an examination of your gas bill to understand how well insulated your home is.

“The first thing we start talking about is insulation,” Cummings said. “We’re going to get your house up to an insulation standard so a heat pump, that can work well below zero, will keep your house warm without backup heat.”

Then they’ll get to know your priorities. Are you looking for a contractor, or do you have the means and will to install on your own?

“We have DIY units that work down to minus 20,” Cummings said, referring to Mr. Cool as an example. If you do want to work with a contractor, they’ll help you find the right one and the right unit for the contractor to install.

Even if you don’t think you’ll go the heat pump route this year, it might be worth getting the ball rolling. Because if your furnace suddenly gives out, you’ll likely be inclined to buy another.

“It takes planning and preparation to transition to a heat pump,” said Bramblett of Energy Smart. “It’s about taking time to prepare before your heating system is about to fail, because that’s when it’s going to be the hardest time to find a good system for your home.”