Heat Pumps 101: How the Public Can Fight Climate Change

Credit Wikimedia CommonsKristoferb

Nations around the world are springing into action with plans to fight climate change. It has been widely accepted that our changing climate is caused primarily by human activity. Greenhouse gases (GHGs) emitted through our everyday activities contribute to climate change. Canadian buildings, including homes, contribute 18% to national emissions (6). Space heating, cooling, and water heating represented approximately 87% of the total Canadian residential emissions in 2018 (8). This article will explore the benefits of heat pumps and important installation considerations, with a focus on space heating and cooling.

Conventional heating equipment burns fuel to heat a building. During combustion, by-products are emitted such as carbon dioxide, sulfur dioxide, nitrogen oxides, and carbon monoxide. This chemical cocktail varies depending on the fuel. Many of these by-products are GHGs that contribute to climate change every time a combustion appliance ignites. Some by-products, such as carbon monoxide, have associated safety risks. The quantity of emissions varies depending on the energy demand of the building and its occupants.

Approximately 50% of residential buildings in Canada use natural gas as the primary energy source for heating and other applications (8). When comparing the by-products of natural gas combustion to the alternative fossil fuels (i.e. coal, oil, propane), natural gas is the cleanest burning fuel. Propane is similar because it is a derivative of natural gas. However, in addition to emitting GHGs during combustion, natural gas poses other climate risks. The primary component of natural gas is methane. Methane is a very powerful GHG, having more than 80x the warming effect of carbon dioxide over the first 20 years of its life in the atmosphere (4). With hundreds of thousands of kilometers of pipeline leading up to every natural gas meter that is connected to Canadian homes, there are countless potential methane leaks along the way.

What are Electric Heat Pumps and Why Should We Care?

Electric heat pumps provide space heating, cooling, and hot water without using fossil fuels. These heat pumps use only electricity and therefore do not produce emissions at the point of use. The opportunity to couple heat pumps to a power grid supplied with clean electricity generated by solar, wind, geothermal, hydro, or nuclear enhances GHG reductions. This means that heat pumps are an essential tool for fighting climate change and you can be a part of this. Across Canada, community-level GHG reduction targets have been set. Waterloo Region, Ontario has set a 50% GHG reduction target to be achieved by 2030, and an 80% reduction target by 2050. Their ambitious climate action strategy, TransformWR (1) (Waterloo Region’s long-term climate action strategy, developed by ClimateActionWR), calls for a widespread transition to electric heat pumps because this can have a significant impact. Taking action now can prevent increases in the deadly climate impacts that are already affecting each and every one of us: forest fires, floods, heat events, and extreme weather.

Heat pumps also have personal benefits for health, comfort, and safety. They eliminate the risk of gas leak explosions and carbon monoxide poisoning (9). Air quality is improved because of the continuous circulation and lack of combustion inside the home (3). Your home will be more comfortable because heat pumps provide a more consistent supply of temperature and move more air throughout the home (9). This helps to reduce the temperature and humidity fluctuations that occur with fossil fuel systems.

How Heat Pumps Work

Electric heat pumps are not a new technology. The first heat pump was built in 1856, well before the first gas-fired central heating system was invented by Alice Parker in 1919. Heat pumps use a vapor-compression refrigeration system. This sounds highly technical, and it is, but you are already very familiar with the technology. The refrigerator in your kitchen works off the same principles, as does a typical air conditioner.

It may sound surprising, but there is plenty of heat energy available outside, even on very cold days. The amount of heat available in the air at -18°C is 85% of that available when the outdoor air temperature is 21°C (7). When heating, heat pumps extract the heat energy from the surrounding air, concentrate it, and move it into the home. Since a heat pump works by moving heat from one location to another, it can be reversed to move heat out of a home in summer, thereby replacing the need for an additional air conditioner.

Today’s heat pumps are very efficient, many times more efficient than conventional systems. Their heating efficiency is reported as the coefficient of performance, or COP, which is the ratio of energy output to input. This ratio can also be communicated as a percentage. In general, efficiencies fall in the range of 200–500% depending on the type of heat pump. This means for every kilowatt of electrical energy used to run the heat pump, 2–5 kilowatts of heat energy are produced. In contrast, heating systems that use fossil fuels typically have efficiencies from 80–97%, as they cannot produce more energy than is contained in the fuel (9). Heat pump cooling efficiencies can also be rated in terms of COP, but are more commonly termed Energy Efficiency Ratio (EER).

Types of Heat Pumps

Residential heat pumps are generally classified as either air source heat pumps (ASHPs) or ground source heat pumps (GSHPs), and there are different configurations within these classes. Here, we focus on cold climate air source heat pumps (cc-ASHP) and GSHPs because they are the most practical in mid-latitude climates where this article was written. We encourage readers to investigate the types of heat pumps that best suit their climate region and applications.

Cold climate air source heat pumps available today are designed to operate at outdoor temperatures as low as -25C. GSHPs, also known as geothermal heat pumps, extract and release heat from the ground where temperatures remain relatively constant year-round. This allows them to operate very efficiently even when it is very cold outside. This is of great advantage not only to the consumer but to utility grid operators as it reduces peak electricity demand in summer and winter as recently discussed in this article (2). Heat pumps can either be installed in a centralized system or as distributed units in individual rooms (known as mini-split heat pumps). To determine the right type for your home, talk to your contractor or consult the resource list at the end of this article.

Financial Costs

Heat pump installation costs vary widely. We cannot offer a meaningful price range because it is very dependent on the type of heat pump and your home’s thermal efficiency. However, keep in mind that a heat pump provides both heating and cooling, eliminating the need to purchase separate heating and cooling systems. There are also ways to reduce costs. Canadians can use the Canada Greener Homes Grant (available at the time of writing), which offers up to $5000 for heat pump installation. This grant provides an additional $600 for an energy audit, which helps determine ways to reduce costs of installation and operation. For example, upgraded insulation and air sealing measures could be suggested. If you live outside of Canada, check out what local and government incentives are available. The best way to determine your installation cost is to get quotes from several contractors. But don’t base your decisions on price alone. The suitability of the heat pump system design to your home, and the quality of the installation process, are just as important.

Depending on your local utility rates and fuel prices, heat pumps may also be cheaper to operate than conventional alternatives. However, with a heat pump you may be able to cut the use of fossil fuels in your home altogether, thereby saving the connection, distribution, and delivery fees. And remember, heat pumps offer so many benefits that justify the costs. Implementing the right technology now can help mitigate climate change, save you from being locked into a fossil fuel source for years to come, and make your home more comfortable.

Conclusion

Climate disasters such as increased forest fires, floods, and extreme weather are already befalling the world. The Intergovernmental Panel on Climate Change (IPCC) has reported that the unprecedented warming on record is unequivocally human-induced (p. 6)(5). Homeowners can directly contribute to turning this around by transitioning to heat pumps for space heating, cooling, and water heating. Learning about the types of heat pumps, their costs, and available incentives can be daunting, but there are many resources available to help. We have listed some below. Take your time, talk to contractors and heat pump owners, and keep organized notes. When you do get a heat pump, tell your friends and family. The choices we make now can help protect us from the climate-related dangers looming in our near future.

Helpful Resources:

A homeowners’s guide to heat pumps for comfort and climate by HVAC professionals and enthusiasts

Airsource Heatpump Buying Guide by Northeast Energy Efficiency Partnerships

IPCC, 2021: Summary for Policymakers. In: Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [MassonDelmotte, V., P. Zhai, A. Pirani, S.L. Connors, C. Péan, S. Berger, N. Caud, Y. Chen, L. Goldfarb, M.I. Gomis, M. Huang, K. Leitzell, E. Lonnoy, J.B.R. Matthews, T.K. Maycock, T. Waterfield, O. Yelekçi, R. Yu, and B. Zhou (eds.)]. Cambridge University Press. In Press.

Consumer Tips by the Heating, Refrigeration and Air Conditioning Institute of Canada

Heating and Cooling with a Heat pump by Natural Resources Canada

Heat Pump Case Studies by the City of Concord, Massachusetts

Geothermal 101 by the Ontario Geothermal Association

TransformWR: Waterloo Region’s Transition to an Equitable, Prosperous, Resilient, Low Carbon Community, 2021, by ClimateActionWR

References:

1. ClimateActionWR (2021), TransformWR, https://climateactionwr.ca/wp-content/uploads/2021/07/Final-TransformWR-Stragegy.pdf
2. Dunsky (2020). The Economic Value of Ground Source Heat Pumps for Building Sector Decarbonization, https://ontariogeothermal.ca/downloads/dunsky--hrai-benefitsofgshps--2020-10-30-.pdf
3. ECOHOME (2021). Heat Pumps: What They are and How They Work, https://www.ecohome.net/guides/2265/heat-pumps-what-they-are-and-how-they-work/
4. Environmental Defense Fund (2021), Methane: A crucial opportunity in the climate fight, https://www.edf.org/climate/methane-crucial-opportunity-climate-fight
5. IPCC, 2021: Summary for Policymakers. In: Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [MassonDelmotte, V., P. Zhai, A. Pirani, S.L. Connors, C. Péan, S. Berger, N. Caud, Y. Chen, L. Goldfarb, M.I. Gomis, M. Huang, K. Leitzell, E. Lonnoy, J.B.R. Matthews, T.K. Maycock, T. Waterfield, O. Yelekçi, R. Yu, and B. Zhou (eds.)]. Cambridge University Press. In Press.
6. Natural Resources Canada (2021), Canada Greener Homes Grant, https://www.nrcan.gc.ca/energy-efficiency/homes/canada-greener-homes-grant/23441
7. Natural Resources Canada (2021) Heating and Cooling with a Heat Pump, https://www.nrcan.gc.ca/energy-efficiency/energy-star-canada/about/energy-star-announcements/publications/heating-and-cooling-heat-pump/6817#b5
8. Natural Resources Canada (2018), Natural Energy Use Database, https://oee.nrcan.gc.ca/corporate/statistics/neud/dpa/showTable.cfm?type=CP&sector=res&juris=ca&rn=20&page=0
9. North East Energy Efficiency Partnerships (2020). Air Source Heat Pump Buying Guide, https://neep.org/sites/default/files/resources/ASHP_buyingguide_5.pdf

Authors:

Jeff Hunter, ClimateActionWR Volunteer, Residential Sector Committee Advisor | Vice-President, Ontario Geothermal Association | Founder, Evolved Thermal Energy Inc.

Monika Wagner, ClimateActionWR Volunteer, Residential Sector Committee | Master of Science-Geography Student

Editor:

Heather McDiarmid, ClimateActionWR Residential Sector Committee Chair, Ph.D., MCC | McDiarmid Climate Consulting