Where did heat pumps come from and why hasn’t your neighbour heard of them?

Heat pump technology isn’t new; it was invented over 150 years ago. First came artificial refrigeration in 1748. Then in 1857, Peter Von Rittinger built the first heat pump system. In 1940, Robert C. Webber developed the first ground source heat pump by modifying his freezer. Mini split air conditioners, or “mini splits,” as we have come to know them, were first introduced in 1968.

Technology is always evolving, like the flat screen TVs that we all have in our homes, which evolved from the tube box that was first marketed to the public in 1939. So, it goes without saying that heat pumps have also gone through a transformation since the first mini split from the late ’60’s.

As an industry leader, Mitsubishi Electric has introduced many firsts to market: the world’s first mini split in 1968, the first inverter model in Canada in 1985, the first ducted model in the Canadian market in 1987, and the first to provide 100% capacity at -20°C (to name a few). And now, Mitsubishi is leading the industry in heat pumps.

You can’t have a conversation about appliances today without mentioning energy efficiency. In the simplest terms, energy efficiency means to use less energy to get the same task done. Many technologies?have become more energy efficient over time. For example, incandescent light bulbs are only about 5% efficient, which means that 5% of the energy is used to generate light while the remaining 95% is wasted as heat. In contrast, an LED is anywhere from 80% to 90% efficient. Another example is gasoline fueled cars with internal combustion engines are only 12% to 30% efficient, whereas vehicles with an electric motor are 77% to 100% efficient?when including the energy recaptured from regenerative braking.

When it comes to heating appliances, fossil fuel appliances can be anywhere from 60% to 97% efficient. An electric resistance (i.e., baseboard) heater or furnace, on the other hand, is 100% efficient. So, 1 KW of energy “input” will give you 1 KW of heat “output”. However, heat pumps don’t create heat at all – they operate on a different principle altogether, instead they transfer thermal energy between two locations using the thermodynamic properties of refrigerants. This allows them to operate much more efficiently, with Mitsubishi models typically ranging between 300% to 500%. Meaning, more thermal energy is produced than the amount of electric energy used to pump it. Amazing, right?

How can a heat pump be so much more efficient?

This is done through the vapour compression cycle, which is what Peter Von Rittinger discovered. This later spawned what is now known as the refrigeration cycle. This is the same cycle used in refrigerators, freezers, and air conditioning units (humans have not yet figured out how to create cold – we can only remove heat).

Let’s briefly discuss how a heat pump works. In a heat pump you have 2 heat exchangers, one we call the Evaporator and one we call the Condenser, but this is interchangeable. A compressor pressurizes the refrigerant from a low-temperature, low-pressure vapour to a high pressure superheated vapour. It then passes through the condenser where it condenses and gives off its heat and becomes a cooled liquid. Then it goes through the expansion valve where its pressure abruptly drops, causing flash evaporation. This process absorbs heat from the air going across the evaporator (like when you open the valve on a propane tank). Because the refrigerant changes state at -29°C at atmospheric pressure, by decreasing the pressure, we can cause vaporization or evaporation at very low temperatures and thus absorb heat energy even from very cold outside air (there is heat in the air until absolute zero or -273°F). Therefore, the refrigerant is doing all the work, which allows for higher co-efficiency of performance. This is simply the ratio of energy in, to energy out. Because a heat pump system is only using electricity to run the fan compressor and circuitry, the amount of heat energy that it can deliver will be far greater than the energy it uses.

A 2022 study from CanmetENERGY suggests that cold climate air source heat pumps are more efficient and cheaper to operate than electric resistance, oil furnaces, as well as natural gas furnaces in most parts of Canada, although cost savings when switching from natural gas furnaces are smaller.[1]

Reducing natural gas usage in the home is not only about energy and GHG emissions reductions – indoor air quality is also of significant importance. A recent article by Emily Chung states that gas stoves produce more indoor air pollutants than anyone expected. Nitrogen oxides, produced when gas is burned, is linked to respiratory problems such as asthma and decreased lung function, especially in children. Others include formaldehyde, nitric oxide, and carbon monoxide, which can be deadly.

Builders across Canada are starting to build new homes with heat pumps as their main thermal appliance. And many people with existing homes are also realizing the benefit of retrofitting their properties with heat pumps.

A Net Zero Home produces as much energy – clean, renewable energy – as it consumes. 98% of all CHBA Net Zero/Ready Homes use air source heat pumps as their primary space heating appliance. By purchasing a Net Zero Home, you’re doing your part to protect against climate change and preserve natural resources for future generations. All of a Net Zero Home’s features work together to significantly minimize your household’s environmental footprint.

For more information on heat pumps, CHBA members can view the Net Zero webinar “Heat Pumps: A More Efficient and Healthier Solution,” featuring Steven Cornelius, Residential Products Business Development Manger at Mitsubishi Electric. The webinar recording and slide deck can be found at chba.ca/nzwebinars.

[1] Note: The results of this study are limited to the home archetypes, energy prices and equipment performance levels assessed and should not be assumed to uniformly apply to other house archetypes, energy prices and/or equipment performance levels.