Over the past several years, I have spent a great deal of time travelling through colder climate regions as electrification efforts accelerated, which is a polite way of saying I am Canadian and spend a lot of time crossing the country for work, talking and learning about HVAC.
It has been incredibly exciting to see the massive wave of heat pump adoption. This adoption has been driven by climate commitments and policies that created a sense of urgency that left little room for hesitation. In the push for electrification, air-to-air heat pumps became the default solution across much of the country. Within this decision, there is an opportunity.
The opportunity is that air-to-air heat pumps were applied as a choice, whereas a more nuanced approach might have been better. But like with any technology, you don’t know what you don’t know! After years of travelling, sitting in meetings, and participating in workshops and contractor roundtables across Canada, a pattern has become impossible to ignore.
In some cases and regions, air-to-water heat pumps might have been the smarter and more resilient choice. The key takeaway is not that one technology is flawed, but that solution selection requires a case-by-case approach. The intent of these observations is to advocate for choosing the right tool for the job.
Whether it’s air-to-water, air-to-air, or ground-source heat pump technology, the choice should be driven by the use and the application. Retrofitting a hydronic system? Air-to-water. Conventional gas/air conditioner? Air-to-air, or better yet, the grid powerhouse of a ground-source heat pump.
Default solution
What I have learned from my travels is that electrification is complicated. Programs need to scale quickly. Installers need solutions they already understand. Incentives need clear and simple categories. Air-to-air heat pumps, which are seen as the natural fit for homes with forced-air ducted systems, checked every one of those boxes.
The primary goal was adoption, and with that can sometimes come unintended consequences. This was nobody’s fault. You don’t know what you don’t know, and in fast-moving markets, technology can outpace policy. If a solution looked too different from a traditional furnace replacement, it could be quietly and unintentionally sidelined. Ground-source heat pumps are unjustly seen as too expensive, and hydronic systems were not top of mind, even though in some areas they still represent a significant share of the housing stock.
That mindset shaped the market. Training dollars flowed toward ducted solutions. Marketing reinforced the idea that electrification meant air-based systems. In the process, a critical question was rarely asked. What actually works best in these buildings?
Winter cold snaps are where system design really shows its value. This was especially clear during a town hall meeting I attended on the East Coast in the middle of winter. The building itself was beautiful, a well-maintained historical building with beautiful cast iron radiators throughout. It should have been the perfect example of thermal comfort and resilient heating. Instead, the room was cold. Two air-to-air heat pumps had been retrofitted into the space, working hard but struggling to deliver comfort in a building designed for hydronics.
Isn’t it ironic
As the discussion turned to grid peaks and winter reliability, the irony was hard to miss. That same building, with its existing hydronic distribution and thermal mass, could have been turned into a thermal battery using an air-to-water heat pump. Heat could have been stored and released gradually, maintaining comfort while helping ride out peak demand.
Homes and buildings equipped with air-to-water heat pumps connected to hydronic distribution can behave differently during extreme weather. Rather than reacting minute by minute to outdoor temperature swings, these systems store heat and release it steadily. These buildings function as thermal batteries. Occupants experience fewer temperature swings and more stable comfort. Installers see systems operating exactly as intended.
The takeaway from these observations is not that one technology is superior to another. Because that wouldn’t be true. The difference is not the heat pump alone. It is the system design and picking the right heat pump for the job.
Heat pumps are an essential part of the electrification solution. But as we build more houses and plan for the future, there will be challenges. The opportunity lies in diversifying the types of heat pumps deployed to ensure a more stable grid and, critically, to deliver predictability and comfort to the consumer.
If a home has a gas boiler, we don’t need to retrofit to an air-to-air to electrify. You also don’t need to use an electric boiler. There are options.
In effect, an air-to-water heat pump can act as a quiet grid asset. When you replace a boiler with an air-to-water heat pump, the results are predictable. The homeowner has the same system they always had, the same level of comfort and a predictable outcome for them. They don’t need to adapt their lifestyle at all.
Missed opportunity
In several of the regions I visited, a surprisingly high percentage of existing homes were still heated by ageing boilers. These homes already rely on hydronic distribution, radiators, or in-floor systems that were designed to deliver steady, comfortable heat in cold climates.
Instead of upgrading those homes with air-to-water heat pumps and transforming them into thermal batteries that could support both comfort and grid flexibility, many were retrofitted with either electric boilers or air-to-air systems shoehorned into buildings that were never designed for ducted heating systems. The result was not a failure of the technology, but a mismatch between the system and the infrastructure already in place.
I’ve been in buildings where the hydronic emitters still existed, pipes capped, and boilers removed. Comfort complaints followed. Homeowners described uneven temperatures and drafts that had not existed before. In trying to electrify, we unintentionally compromised the very comfort these systems were meant to improve.
I will remind everyone that this is not a knock against a type of heat pump. Every heat pump technology has an important role to play. The issue arises when we effectively pick a single winner, rather than supporting a range of solutions that allow buildings to be treated as energy assets. When technology advances faster than policy frameworks, we risk locking in outcomes that fall short of what is possible.
A different approach
If these electrification efforts were starting today, the playbook could look different. Technology selection could be based on building type and heating type rather than technology familiarity alone.
Air-to-air heat pumps would still play a significant role, but air-to-water systems would be prioritized where hydronic distribution is available. This emphasis on leveraging existing hydronic infrastructure and thermal storage is the crucial differentiator for long-term resiliency. Incentive programs would reward system performance, not just equipment type. Thermal storage would be recognized as infrastructure, not an accessory.
Canadians didn’t make these choices out of ignorance or bad intent — we made them under pressure; speed mattered, simplicity mattered, but now, real-world data and contractor experience are telling a clearer story. The next phase of electrification won’t be defined by how fast heat pumps can be installed. It will be defined by how well they serve homeowners, trades, and the energy system as a whole. Choosing the familiar solution is easy. Choosing the right one takes a bit more thought.