Be prepared to advocate for hydronic-based heat pump systems

Ask some average people you cross paths with this question: Have you ever heard of something called a heat pump? Chances are that many of them will say yes.

Follow up with another question: Can you tell me what a heat pump does? Most of those who answered yes to your first question would likely say it does something that keeps a house warm in winter.

Pose one more question to those who - so far - seem to have familiarity with heat pumps: Can you tell me how a heat pump works?

Now we’re getting into the weeds. I suspect that very few of those people can give an accurate description of how a heat pump works. The few that do will probably say something like: It’s a machine that somehow uses outside air to make warm inside air.

There's truth in that statement. The majority of heat pumps used in North America remove heat from outside air and use it to create warm air inside. That’s why those of us in the trade call them as “air-to-air” heat pumps. But that response is also incomplete. It doesn’t recognize how heat pumps can provide comfort without relying on forced air delivery.

Abundant support: Why is it that so many people have at least heard of heat pumps? It’s because some of the money you pay in taxes and for utility bills has been used to promote and incentivize their use. There’s no shortage of government and utility programs that encourage and help underwrite the installation of air-to-air heat pumps. On any given day the average consumer is likely to hear radio advertising, see billboards as they commute, or get a flyer in their mailbox encouraging them to use heat pumps rather than fossil fuel to heat their home. If they responded to any marketing outreach they’re probably receiving daily e-mails reminding them of the virtues of those little white boxes on the wall that deliver warm air in winter and cool air in summer.

Almost all of this promotional effort is directed toward air-to-air heat pumps, and to a lesser degree, water-to-air geothermal heat pumps. Very few current promotional efforts describe how heat pumps can be used in combination with hydronic systems.

When a homeowner with a hydronic heating system contemplates using a heat pump they’re likely to begin their search with local HVAC installation companies. At that point there’s no telling what “professional” advice they’re offered. Perhaps some of that counseling includes the following:

Nope: A heat pump can’t work with hydronic heating. Sorry…
There are some hydronic heat pumps, but they can’t heat water over 120 ºF, and so they won’t work with your existing radiators.
I know you like the comfort of your hydronic heating system, but there’s no way I can modify it to provide cooling.
Why not turn off that “outdated” hot water system, and let us upgrade you to a multi-zone ductless heat pump system.

Many of you know that that these responses are either not true, or don’t fully describe what’s possible. Instead they discourage using heat pump with hydronic-based systems.

Different Audiences: It shouldn't be surprising that most homeowners don’t spend much time thinking about heat pumps or hydronics, much less how they can work together. But what about “energy professionals?” People who work with HVAC systems every day, or influence government policies that ultimately shape - or skew - the market for multitudes of current and future consumers. What do they know, and what should they know, about the overlap of heat pumps with hydronics?

I’ve had opportunity to work with quite a spectrum of building and energy professionals over the years. I’ve listened to their viewpoints, asked them questions, and considered their recommendations. Nearly all of them have good intentions and want to provide what they consider as efficient and environmentally sound solutions for heating and cooling buildings.

Still, I’ve noticed that many of these folks have a rather limited perspective of what hydronic systems are, or what they are capable of. There’s a hesitancy, or in some cases a “fear” to venture beyond ducted (or ductless) delivery systems for heating and cooling. It’s not necessarily a limited familiarity with hydronic heat pumps that creates this aversion, but rather the perceived complications associated with using water rather than air as the energy delivery method.

Although these professionals carefully scrutinize technicalities such as COP, SEER, HSPF, proper equipment sizing, and smart thermostats, there’s virtually no consideration of distribution efficiency, radiant vs. convective heat delivery, human physiological comfort, providing domestic hot water as well as space heating, or small-scale chilled water cooling.

Perhaps you’ve interacted with similar professionals who have obvious reservations when it comes to combining heat pumps with hydronics. You want to present a case for such systems with complete and truthful information, but aren’t sure how to approach the subject from their standpoint. To that end, here are some suggested talking points for different groups of professionals that may help lessen their reservations and encourage further consideration of hydronic systems supplied by heat pumps.

HVAC installers and technicians: For decades hydronic systems have used boilers as their sole heat source. When properly designed and installed these systems have provided superior heating comfort, but had nothing to offer when it came to cooling. Now, hydronic heat pumps can be used as stand-alone heating and cooling sources, or in combination with boilers. They can also supply domestic hot water. Considering all the pending electrification mandates, heat pumps are assured of capturing an increasing share of the hydronic heating and cooling market. Learning more about hydronic heat pumps equips you to take advantage of these trends, design reliable and efficient systems, and profit as the market expands.

Be prepared to advocate for hydronic-based heat pump systems from the standpoint and needs of the consumers and professionals you interact with. Support the discussion with examples, be prepared to allay the “fear factor,” and don’t capitulate to the push back that it’s all about price.

Engineers & Architects: Prospective clients are increasingly requesting low-carbon, resilient heating and cooling solutions for their buildings. The combination of heat pumps with modern hydronics offers a highly versatile “enabling” technology that can adapt to specific project requirements. Hydronic-based approaches minimize or eliminate concerns about refrigerant leakage inside buildings, or compatibility of the building’s distribution system with future refrigerants. Hydronic system can accommodate evolving technologies such as thermal energy storage in combination with time-of-use electrical rates. Hydronic systems using heat pumps as their primary heating and cooling source provide your clients with a low-carbon approach to heating, cooling, and domestic water heating. Those systems can also integrate - and even enhance - heat recovery ventilation allowing for a complete HVAC solution.

Industry influencers and decision-makers: Some heating professionals think of hydronics as an antiquated method of heating buildings. Nothing could be farther from the truth! Modern hydronics technology using heat pumps can provide superior heating and cooling comfort. It can do so with significantly lower primary energy inputs compared to other approaches. A technology with roots in the 1800s has evolved into a versatile, elegant, and highly efficient way to deliver year round comfort in the 21st century.

Utilities & Energy Planners: There are many utility and government programs that incentivize the use of modern heat pumps as a key path for decarbonization. However, most of them currently don’t address an important market segment - how to decarbonize existing hydronic heating systems. Air-to-water as well as geothermal water-to-water heat pumps provide a solution. These heat pumps can be combined with existing boilers to shift the majority of seasonal heating energy away from fossil fuels while still providing for supplemental and backup heating with minimal effect on peak electrical demand. They can also be designed with thermal storage subsystems to leverage time of use electrical rates, and reduce peak power demands.

Face It & Embrace It: In North America, advocates for hydronic-based heating, and cooling, have been fighting an uphill battle for decades. The hydronics market has been at a disadvantage when it comes to requisite design and installation skills, hardware cost, and the “viral” consequences of poor installations. Try as it might, our industry has had limited success in convincing consumers as well as energy and building professionals that hydronic-based systems have the potential to deliver many benefits not attainable using forced-air systems.

The recent ground swell of interest in heat pumps across a wide swath of society presents a new opportunity to rekindle interest in hydronics. We don’t have to let the ductless heat pump industry “eat our lunch” as trends such as net zero construction, resilient design, and decarbonization become the market drivers. We have technically solid solutions that can not only leverage these trends, but do so without compromising comfort.