Canada’s commitment to decarbonization is disrupting how we heat and cool our homes, promising both challenges and incredible opportunities. As we all know, Canada is committed to decarbonization and that means we are seeing a dramatic change in how we heat and cool our homes. Commercially, this new decarbonization goal is going to introduce hurdles and technical challenges that policymakers must address before we face what may be some insurmountable obstacles as we attempt to retrofit large commercial boilers to heat pumps using current technology.
In Canada, there is a national emphasis on adopting environmentally sustainable practices. Our political and industry leaders are and must continue to devise innovative strategies to address the challenges associated with this transition. It is crucial to resist the defeatist attitude of “we can’t do it, so we won’t.” Instead, we must leverage existing technologies and continue to innovate to meet our 2050 goals.
Canada is targeting a reduction of greenhouse gas emissions by 45 per cent below 2005 levels by 2030. Decarbonization and electrification, as part of our climate change strategy, will boost economic growth by creating new sustainable careers.
The residential market holds immense potential in decarbonization and electrification, particularly with the significant role hydronics can play in offering heating, cooling, and domestic hot water in uniquely efficient ways. By delivering green, sustainable heating, cooling, and domestic hot water through new hydronic system installations, retrofits, and hybrid systems, we can effectively address the needs of Canadians, especially in the colder northern regions.
The advantages
I am not against boilers in any way. Those who insist that all boilers must be phased out must remember the landscape of our industry, the building environment, and the practical realities we face. For instance, I initially doubted the practicality of using phase change batteries with gas appliances, but I was proven wrong. A recent study in the United States demonstrated that reducing gas consumption by up to 50 per cent can be achieved using thermal storage while keeping boilers in homes.
Despite the benefits and reliability of boilers, air-to-water heat pumps offer some unique advantages. These systems can provide both heated and chilled water, eliminating the need for separate appliances for heating and cooling. In my home, I replaced a noisy air conditioner with an air-to-water heat pump, installed with the help of TJL Mechanical and Koolen Electric. I removed the DX coil from my existing plenum and installed a new hydronic A coil, which now moves chilled water in the summer and heated water in the winter.
For domestic hot water, I utilize two new technologies: an indirect tank and a self-contained unit that converts my home’s hydronic heating supply to provide on-demand domestic hot water, both specifically designed for heat pumps and low temperatures. My air-to-water heat pump is connected to a buffer tank for two important reasons: to ensure continuous heating or cooling even when the unit is making domestic hot water, and to experiment with load shifting, allowing me to take advantage of lower overnight electricity rates to heat and cool my home.
Reducing operating costs
At this point, you all are aware that various technologies allow you to electrify your home, providing heating, cooling, and domestic hot water. For instance, combining an air-to-air heat pump with a heat pump water heater can achieve these goals at a cost comparable to a single retrofitted air-to-water heat pump and in some cases, the air-to-air solution costs less money. For me, the decision between air-to-air or air-to-water is not about technology and cost, it is about the people.
In the case of my home, the air-to-water was the right solution for a variety of reasons. Not only am I doing heating, cooling and DHW, but I am also using a buffer tank as a thermal battery that enables the equipment to operate during off-peak hours, taking advantage of the coefficient of performance (COP) of air-to-water heat pumps and timing it with off-peak rates. Typically, air-to-water heat pumps have a COP ranging from three to five. To simplify, imagine buying one Timbit at Tim Hortons and receiving four in your bag. That’s what a COP of four represents.
While air-to-air heat pumps also have high COPs, the key advantage of air-to-water heat pumps lies in their ability to store thermal energy for later use. With a water-based or other thermal battery, you can charge the battery during off-peak hours and use the stored energy when needed.
As an example, if you live in an area of Ontario where the off-peak electricity rate is 8.2 cents per kWh and the on-peak rate is 17 cents per kWh, you can save up to 50 per cent by running your air-to-water heat pump during off-peak hours and storing the energy for later use. This not only takes advantage of lower overnight rates but also leverages the high efficiency of the heat pump’s COP.
Environmental impact
Another interesting aspect to consider is the impact of off-peak electrical usage on carbon reduction. It was not until recently that I realized the significant potential after an interesting discussion about our grid and the sources of fuel for the grid with a friend at the utility. When we use electricity during off-peak hours, we primarily tap into cleaner energy sources, which not only results in energy savings but also promotes infrastructure stabilization and carbon reduction.
Ontario’s electrical grid is composed of various energy sources, with a significant portion coming from low-carbon options. According to the Independent Electricity System Operator, in 2020, Ontario’s energy mix included approximately 60 per cent nuclear, 24 per cent hydroelectric, seven per cent natural gas, seven per cent wind, two per cent solar, and less than one per cent bioenergy.
During peak hours, the grid often supplements with natural gas plants, which are more carbon intensive. During off-peak hours, the demand is lower, and the grid can rely more on stable, low-carbon sources such as nuclear and hydroelectric power. This shift not only reduces greenhouse gas emissions but also alleviates the strain on the electrical infrastructure.
By leveraging off-peak electricity for air-to-water heat pumps, homeowners can significantly contribute to carbon reduction. During off-peak periods, the carbon intensity of Ontario’s grid can be as low as 20 grams of CO2 per kWh, compared to over 200 grams during peak periods when natural gas is more heavily utilized.
The future is green
Some will rightly note that water-based storage as a thermal storage device has limitations. Water-based storage captures sensible energy but not latent energy, requiring large vessels to store enough energy. However, recent advancements in phase change materials are set to revolutionize our industry. PCM batteries can store both latent and sensible energy, providing up to four times the energy in a smaller footprint.
Another exciting development we’re witnessing is the evolution of combination air-to-air equipment. I’m currently involved in a pilot project with a builder in London, Ont, where we’re using an air-to-air heat pump integrated with a PCM battery. This new air-to-air heat pump, like a ground-source heat pump, features a secondary coil capable of producing hot water. In this test case, the air-to-air heat pump with a PCM battery is connected to the domestic heat exchanger in the unit, allowing us to produce up to 80 gallons of domestic hot water during off-peak hours. We can heat the water for less than gas and we also potentially have a positive carbon contribution by doing so.
Innovations like this make me cautious about ruling out gas, hydrogen, or any other existing technology entirely. We have no idea what groundbreaking technologies are just around the corner and how they might impact the industry.