The 5 biggest industry myths about air-source heat pumps

November 4, 2022 by Zack Mast and Justin Margolies

The electrification of residential HVAC will require a major shift in people's thinking at every level. Some misconceptions about air-source heat pumps still get in the way of designing effective programs to get heat pumps installed in more homes.

Kevin DeMaster, Senior Manager for Utilities & Electrification at Mitsubishi, has dedicated his career to advancing energy efficiency in utility programs and the marketplace; he even spent four years at Slipstream (WECC) developing better DSM programs. In 2014, Kevin joined the manufacturer side to connect utility programs with an insider's perspective and advance innovative HVAC technologies.

Kevin's role as a manufacturer gives him unique insights into some of the misconceptions among program implementers, evaluators, and contractors that can often get in the way of effective program design.

MYTH #1: Programs should define separate measures for "mini splits" and "air-source heat pumps"

In the need to define specific incentives for specific measures, programs often make the wrong distinction. "A lot of times programs might create separate measures," Kevin says. "They'll say, well, we've got a mini split heat pump measure—we're gonna give a rebate on that. And we're gonna give a separate rebate for air-source heat pumps."

But there's a problem with that distinction. "They're all heat pumps! They all do the exact same thing."

Under this misconception, when a program uses "heat pump," it typically refers to a centrally ducted system. A "mini split" measure may refer to a heat pump applied to a single room or ductless distribution system.  "However, even 'ductless' is an antiquated term," Kevin says. "The product category is so advanced that there are numerous indoor units, from non-ducted to a range of ducted or any combination of the two, and in a variety of BTU capacity to meet the needs of the space or zone." 

A better distinction, Kevin says, would be to break down heat pumps into two categories:

  1. Single-speed—or two-speed compressors
  2. Variable-speed (sometimes called "inverter") compressors

Under these categories—which Slipstream compared in our dual-fuel study in Michigan—the distinction for measures becomes clearer. Programs can focus on a) whether the technology involves a heat pump and b) the levels of performance within that heat pump." I could have a ductless unit that's in a wall mount or in a ceiling cassette or mounted on the floor, similar to a radiator replacement. Those are all ductless products, but there's multiple configurations," Kevin says. "But we have the full suite of products that operate traditionally like a fully ducted system or low- and medium-static ducted system to address smaller zones. They just have the benefit of a variable-speed compressor and modulation of refrigerant.

"That's really the key and the beautiful part about mini-split technology—you can mix and match any combination of those systems together on a multi-zone system."

A better takeaway: Keep programs as simple as possible

"All a program needs to do is say 'We have incentives available. Ask a participating contractor about details.' Keep it as simple as you can for a contractor to understand, a midstream distributor to execute, for a customer to participate," Kevin says. "Make the program visible, make it transparent. Make it loud."

MYTH #2: Heat pumps don't heat in cold climates

Contrary to common opinion, ASHPs are effective in cold climates–but a lack of customer awareness remains a big issue. One problem is that customers are just beginning to hear about air-source heat pumps, so they might think it's a new technology. It's not.

"At Mitsubishi we've had our Hyper-Heat product line for at least a decade," Kevin says. "Our latest generation is guaranteed to provide 100% heat at negative five degrees Fahrenheit. We've solved the problem and the product continues to advance."

(Editor's note: Kevin represents just one view from a manufacturer, but his point that ASHPs are effective in cold climates is backed by research. For a report on air-source heat pumps in cold climates, we recommend this study in Minnesota from the Center for Energy and Environment.)

Kevin is also quick to remind us of the Department of Energy's recently announced Residential Cold Climate Heat Pump Challenge, which will motivate manufacturers to increase the supply of effective heat pumps.

The terminology around cold-climate effectiveness can add to the confusion. "One misconception I've heard is, well, if it's an inverter compressor or a variable-speed compressor, it must be a cold climate heat pump," Kevin says. "Any 'cold-climate product' that I know of on the market is a variable-speed compressor, yes. But 'variable-speed compressor' does not automatically mean 'cold climate'."

Like a lot of misunderstandings, that's only a slight twist of logic compared to reality.

A better takeaway: Tie incentives to how contractors achieve energy savings

When a contractor enters a customer's home, they're not thinking about how an evaluator has rated the effectiveness of a heat pump. They're thinking about how to keep the house comfortable.

"Understand that it's a puzzle for contractors to solve the occupant comfort question," Kevin says. "That's what we really need to be evaluating when we talk about how it's applied by contractors. Just to throw out a technology based on an evaluation that says it didn't produce is not the right way to go about it."

We might think we make programs simpler by assigning rebates based on product ratings such as Seasonal Energy Efficiency Ratio (SEER) or Heating Seasonal Performance Factor (HSPF). But that approach can limit a contractor's ability to meet the customer's needs—and deliver the most efficiency from a heat pump.Instead, Kevin says, programs can tie incentives to where the energy savings truly are.

"Let the contractor solve the customer's problem. I guarantee you the savings will be there. And if the configuration includes a variable-speed heat pump, the savings will be substantial."

MYTH #3: Evaluators always understand heat pumps

Plenty of evaluators understand how heat pumps work. However, evaluators don't always have the experience to understand the ways contractors configure heat pumps to create a comfortable environment in an individual home.

Kevin insists that everyone in the industry—from implementers to evaluators—needs to be an expert in the technology if we're going to improve heat pump adoption.

"How the technology actually works when we put it in homes—that's what evaluators need to know and become experts on," Kevin says. " In contractor trainings, it's not a one-to-one swap with an air conditioner, right? The contractor thinks, ‘Okay, I go into home and I see the little puzzle box. I need to do this and this to get the heat pump to work right.' The industry needs to know what contractors do. They solve these little puzzles."

A better takeaway: Get manufacturers' input

Program implementers and designers should engage with manufacturers often. But that doesn't mean you have to commit to a single manufacturer. "Get all our input!" Kevin says.

"For so long we've heard, 'Well, we can't be tied to a manufacturer for a program because we don't want to seem biased.' We're not asking for bias. Work with every manufacturer that will step up and help, Embrace manufacturer engagement at every level, every manufacturer. Just because they don't participate [in your programs] doesn't mean you should keep Mitsubishi or anyone else at arm's length."

Policymakers let every car manufacturer weigh in on electric vehicle (EV) policy—so why should it be different with heat pumps? "Keep going forward with those who will work with you. We all have a common objective that we need to solve."

MYTH #4: "Heat pump" is a term that resonates with customers

"From a consumer's perspective, the terminology can be confusing," Kevin says. "When you use the term 'heat pump,' customers might believe this is a heating-only product."

That misconception gets in the way of adoption. According to Kevin, "Mitsubishi contractors say that most of their sales start because the customer wants cooling, and that leads to a recommendation for a heat pump."

If customers innately understood that heat-pump technology is designed to cool their homes, they might be more inclined to start those conversation themselves.

A better takeaway: Have an industry-wide discussion

How do we enforce the message to customers that "heat pumps" work both ways? Outlets such as Canary Media have asked whether heat pumps need a rebrand. It's a conversation worth continuing.

We might suggest a rebrand to "two-way air conditioner"—a simple twist on a term that's already familiar to customers. Whatever we decide to call them, clearing up this misconception would go a long way toward driving direct demand for heat pumps.

MYTH #5: Contractors have written off heat pumps forever

Some contractors might have encountered heat pumps in the 1970s, decided they won't work in cold climates, and never considered them again. But that doesn't mean that they can't adapt to a widescale shift in the products they offer.

Again, it comes down to solving customer's problems.

"Technology advances. Over time, contractors have watched as air conditioners use less energy and put out better cooling at lower energy output. So why couldn't the heat pump work at sub-zero temperatures?," Kevin explains

Busy contractors might not have kept up with the technology. And one bad experience might have soured them for life. Or they might just be thinking about how business has always been done.

It's up to us—as program designers, as educators, as distributors, as researchers—to help contractors understand how heat pumps can help them solve customers' problems and decarbonize at the same time.

A better takeaway: Make contractors our educational partners

We need to invest in contractor training and education to make them our partners. Slipstream collaborates with utilities on initiatives such as on-demand contractor trainings and the Michigan Heat Pump Collaborative to engage stakeholders at all levels of the market, including contractors.

One way programs can help, Kevin suggests, is to set specific heat pump rates to account for the volatility of gas prices. Contractors could more confidently pitch the benefits of a heat pump if they knew a customer wasn't going to balk at the ever-changing costs of fuel.

In the end, clearing up misconceptions is just one step toward transforming the market for heat pumps. Contractors, customers, and program implementers all need the right information to prepare for the disruption of widespread electrification.

"In the U.S., we've been abundant on fossil fuels," Kevin says. "It's just the way of life that we're comfortable with. This is a change in people's thinking—it's going to take some time."

Learn more about heat pump initiatives

Slipstream currently works with multiple utilities throughout the Midwest to compile and distribute best practices for the air-source heat pump market. We are happy to engage with utilities to design better programs and encourage heat pump adoption.

Read more about Slipstream's work in heat pumps.

Attend on-demand trainings as part of the Michigan Heat Pump Collaborative.

Attend online trainings designed for Illinois contractors.