Boosting the efficiency of appliances and equipment cuts GHG emissions by reducing the amount of electricity used to operate these devices. Efficiency improvements also lead to reduced peak demand, less strain on the electric grid, and potential utility savings for homeowners due to the reduced electricity use. Despite this potential, the increase in the total number of households and average ownership of appliances, especially in low- and middle-income countries, has offset the impact of efficiency gains and resulted in increased electricity consumption from devices globally. We conclude that Boost Appliance and Equipment Efficiency is “Worthwhile” because it functionally reduces the energy consumed by these devices, but significant leaps in efficiency and shifts in user behavior are needed to realize its full potential as a climate solution.
Based on our analysis, boosting appliance and equipment efficiency is a promising strategy for reducing GHG emissions, but significant leaps in efficiency and shifts in user behavior are needed to mitigate the rebound effect and realize its impact. This potential climate solution is “Worthwhile.”
| Plausible | Could it work? | Yes |
|---|---|---|
| Ready | Is it ready? | Yes |
| Evidence | Are there data to evaluate it? | Yes |
| Effective | Does it consistently work? | Yes |
| Impact | Is it big enough to matter? | No |
| Risk | Is it risky or harmful? | No |
| Cost | Is it cheap? | Yes |
Appliance and equipment efficiency typically refers to larger devices in residential buildings that run on electricity, such as refrigerators, freezers, washing machines, dishwashers, dryers, and televisions. Energy-efficient appliances or equipment will consume less electricity when operated compared to inefficient devices. Therefore, boosting appliance efficiency reduces the CO₂, methane, and nitrous oxide emissions from electricity generation. As of 2022, the energy consumed by household appliances globally was more than twice the total energy used to cool both residential and nonresidential buildings, and about half the energy used for heating. To drive higher efficiency for these devices, various countries have established regional energy efficiency standards, rating systems, and labeling programs. Currently, homeowners can readily access a variety of options on the appliance market, and less efficient devices can easily be replaced. However, income levels, especially in low- and middle-income countries, may affect people’s actual ability to purchase certain appliances, although these devices are increasingly becoming cheaper.
Improving the efficiency of appliances and equipment functionally reduces the energy required to run these devices. Various field studies have demonstrated the effect of efficiency gains on lowering electricity consumption. However, the rise in appliance ownership per household and the growing total number of households have offset the collective climate impact expected from efficiency improvements. Globally, the number of households grew from about 1.5 billion in 2000 to 2.2 billion in 2021. Considering the concurrent increase in the global average units owned per household, the number of appliances in use has essentially doubled over the same period. For example, we estimate that over two decades, the number of television units owned grew from about 1.4 to 2.8 billion units, refrigerators grew from 0.9 to 1.7 billion units, and washing machines grew from about 0.6 to 1.1 billion units. This growth resulted in rising electricity consumption by appliances annually, from 2,880 TWh in 2000 to 5,734 TWh in 2022, which translates to a 99% global increase, largely driven by the Asia-Pacific region.
Boosting appliance and equipment efficiency allows homeowners to realize operational cost savings as a result of lower electricity consumption and utility bills. Compared to less efficient devices, using appliances with higher efficiency ratings functionally reduces peak electricity demand, alleviating strain on the electric grid. The advent of smart devices and the Internet of Things (IoT) also helps to automate the operation of these appliances, and thereby optimize their runtime while minimizing the energy consumed. Initial purchasing costs are also declining, making efficient appliances more accessible and affordable. Access to high-efficiency appliances also yields additional benefits. For example, access to energy-efficient refrigerators and freezers means that food waste can be minimized with less energy, leading to better food security. Similarly, multimedia equipment, such as television sets, offers access to critical information. Further cuts in GHG emissions are also possible as the electric grid transitions to renewable energy sources.
Despite the potential benefits, the efficiency improvements in household appliances and equipment have not effectively translated into a positive climate impact. This is largely due to the significant rebound effect, or the increase in appliances owned by households as these devices become cheaper and more efficient. Considering the role of appliances in providing a greater quality of life, limiting the increase in appliance purchases is dismissible. The markets for appliances and equipment in many countries also still consist of pre-owned devices, which are less efficient. Some countries, such as Ghana, have established legislation to prevent the importation of pre-owned devices. This approach ensures that the appliances bought by homeowners will run on the newest, most efficient technologies. Recent findings from regions with stringent energy rating systems also suggest that regulations and programs can lead to a 50% cut in the electricity consumed by appliances. Global initiatives, such as the United for Efficiency (U4E) partnership, which seeks to shift appliance markets in low- and middle-income countries into high-efficiency devices, are increasingly needed for the potential energy savings to be realized as a climate solution.
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Low-flow fixtures reduce GHG emissions by reducing the volume of hot water that is used and therefore reducing the emissions from the energy used to heat that water. Reduced water usage also leads to fewer emissions from treating and pumping water for domestic use. Low-flow fixtures are low-cost and simple to install. They generate utility bill savings for households and support sustainable water resource management. Modern quality low-flow fixtures have resolved many of the performance issues of earlier versions. Even with significant adoption, however, the total emissions reduction potential for low-flow fixtures is relatively small. We conclude that, despite its modest emissions impact, Use Low Flow Fixtures is “Worthwhile” due to its relative ease, low cost, and additional benefits.
Based on our analysis, using low-flow fixtures is a cost-effective strategy for reducing water consumption, but has only a modest impact on GHG emissions. Therefore, this climate solution is “Worthwhile.”
| Plausible | Could it work? | Yes |
|---|---|---|
| Ready | Is it ready? | Yes |
| Evidence | Are there data to evaluate it? | Yes |
| Effective | Does it consistently work? | Yes |
| Impact | Is it big enough to matter? | No |
| Risk | Is it risky or harmful? | No |
| Cost | Is it cheap? | Yes |
Low-flow fixtures lessen the total consumption of water by reducing flow rates through a household faucet or shower. Less hot water use means fewer emissions from the energy source used to heat the water, and it also means fewer emissions from pumping and treating tap water. Heating water for showers, sinks, and other domestic appliances is often the second largest source of emissions from buildings after space heating. Modern low-flow showerheads can produce comparable pressure and coverage to traditional showerheads through aeration and/or laminar flow. Aerators for faucets and low-flow showerheads are relatively low-cost investments that users can install themselves.
Low-flow fixtures reduce emissions from heating, delivering, and treating water by reducing the hot water consumption. There is ample evidence for water savings with low-flow fixtures, as well as for the linkage between quantity and source of energy used for water heating and GHG emissions. Additionally, there is substantial research on the emissions from treating and pumping water, which can be reduced through water conservation. Low-flow fixtures are readily available, and performance labels are available to help consumers select quality products.
Low-flow fixtures conserve water, which reduces emissions, reduces energy demand, saves consumers money, and helps with sustainable water resource management. Households that adopt low-flow fixtures can enjoy significant utility bill savings because these fixtures reduce both water consumption and the energy used to heat water in the home. Faucet aerators also produce a smoother water stream with less splashing, and along with low-flow showerheads, are low-cost and simple to install. Household water conservation practices, such as low-flow fixtures, can help with regional sustainable water resource management and defer infrastructure expansion projects. This is particularly important in areas where water resources are increasingly strained due to climate change, growing populations, and other factors. In some regions, community water conservation efforts have had measurable impacts on water treatment costs, resulting in lower water rates for consumers.
Even with widespread adoption, low-flow fixtures would have a relatively small impact on GHG emissions. Moreover, the low cost and ease of replacement mean that low-flow fixtures can be easily reverted to less efficient fixtures, eliminating the emissions impact and other benefits. Lastly, although modern quality low-flow showerheads are comparable to traditional fixtures, the poor quality of early low-flow showerheads may have contributed to decreasing levels of adoption in some areas.
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Heat pumps use electricity to efficiently move heat from one place to another. This solution focuses on the replacement of fossil fuel-based heating systems with electric heat pumps. Heat pumps are remarkably efficient because they collect heat from the outside air, ground, or water using a refrigerant and use a pump to move the heat into buildings to keep them warm in the colder months. Heat pumps typically replace heating systems such as boilers, furnaces, and electric resistance heaters and many will also replace air conditioners, because the same pump can move heat out of a building in the warmer months.
Heat pumps use a refrigerant cycle to move heat. When the liquid refrigerant enters a low pressure environment, it will absorb heat from the surrounding air, water, or ground as it evaporates. When the refrigerant vapor is compressed, it will condense back into a liquid, releasing the stored heat into the building. By passing the refrigerant through this cycle, heat can be moved from outside to inside a building. Absorbing heat from the outside gets more difficult as temperatures drop but modern cold climate heat pumps are designed to work effectively at temperatures approaching –30°C (–22°F) (Gibb et al., 2023). The freezer in your home uses the same technology, moving heat out of the cold box into the warm room to keep your food frozen. In most systems, the refrigerant cycle in a heat pump can be reversed in the warmer months, moving heat out of a building to ensure its occupants are comfortable year-round.
Heat pumps are very efficient at using electricity for heating. This is because they move heat rather than generating heat (e.g., by combustion). For example, a heat pump may have a seasonal coefficient of performance (SCOP) of three, meaning it can move an average of three units of heat energy for every unit of electrical energy that it consumes. Conventional combustion and electric resistance heaters cannot produce more than one unit of heat energy for every unit of fuel energy or electrical energy provided.
Heat pump systems may be all-electric or hybrid, where a secondary fossil fuel-based heating system takes over in colder weather.
A heat pump’s potential to reduce GHG emissions depends on the heating source it replaces and the emissions intensity of the electricity used to run it. When heat pumps replace fossil fuel-based heating, they displace the GHG emissions – primarily CO₂ – generated when the fuel is burned. When replacing electric resistance heaters, heat pumps reduce the GHG emissions from the electricity to power the system because heat pumps are much more energy efficient. As electrical grids decarbonize, the GHG emissions from operating heat pumps will decrease.
All-electric heat pumps provide the most climate benefit because they can be powered with clean energy, but hybrid heat pumps also play an important emissions-reduction role. Hybrids consist of a smaller electric heat pump system that switches to fuel-based heating systems in colder weather. They may be attractive due to lower upfront costs and because they have lower peak power demand on cold days, but hybrids also have a smaller emissions impact. The cost and emissions analysis assumed all-electric air-source heat pumps while the data used in the adoption analysis included all types of heat pumps with the expectation that all-electric versions will dominate in the longer term.
In this analysis, we calculated effectiveness and cost outcomes from specific countries with high heat pump adoption (European countries, Canada, the United States, Japan, and China) to avoid comparing research studies that use different assumptions. The analysis used global assumptions for heating system efficiency: 90% for fueled systems (International Gas Union, 2020), 100% for electric resistance (U.S. Department of Energy [U.S. DOE], n.d.), and SCOP of three for heat pumps (Crownhart, 2023). We also assumed all existing fueled systems use natural gas, which is currently the dominant fossil fuel used for space heating globally (International Energy Agency [IEA], 2023b). The analysis does not include emissions or costs from cooling but does assume the heat pump is replacing both a heating and cooling system.
The cost and effectiveness analysis focused on residential heating systems for which more data are available and also because large variations in the cost and size of commercial systems make it more challenging to estimate their global impacts. Commercial heating systems are typically larger and their emissions impacts are expected to be proportionally greater per unit. Cost savings may be different due the greater complexity of heating and cooling systems (Tejani & Toshniwal, 2023). Available data on heat pump adoption, on the other hand, typically include both residential and commercial units. Our adoption analysis therefore included both residential and commercial buildings, with greater adoption assumed in the residential sector.
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Zhou, M., Liu, H., Peng, L., Qin, Y., Chen, D., Zhang, L., & Mauzerall, D. L. (2022). Environmental benefits and household costs of clean heating options in northern China. Nature Sustainability, 5(4), 329–338. Link to source: https://doi.org/10.1038/s41893-021-00837-w
Heather McDiarmid, Ph.D.
Stephen Agyeman, Ph.D.
Ruthie Burrows, Ph.D.
James Gerber, Ph.D.
Sarah Gleeson, Ph.D.
Yusuf Jameel, Ph.D.
Daniel Jasper
Jason Lam
Cameron Roberts, Ph.D.
Alex Sweeney
Eric Wilczynski
Aiyana Bodi
Hannah Henkin
Jason Lam
Zoltan Nagy, Ph.D.
Ted Otte
Amanda D. Smith, Ph.D.
Our analysis showed that each all-electric residential heat pump for space heating reduces emissions by an average of 0.95 t CO₂‑eq/yr per dwelling (20-yr and 100-yr basis, Table 1).
Heat pumps reduce emissions by reducing the amount of fossil fuels burned for space heating or by reducing the use of less efficient electric resistance heating. Operating a heat pump generates no on-site emissions except refrigerant leaks which are addressed by the Improve Refrigerant Management solution. Our analysis included the emissions from the electricity used to power heat pumps. Thus, the emissions reduction from heat pump adoption is expected to improve as electricity generation incorporates more renewable energy (Knobloch et al., 2020).
There are significant regional differences in heat pump effectiveness due to the electricity mix, climate, and types of heating systems used today (Knobloch et al., 2020). The global average is weighted based on regional heating requirements and existing heating technologies.
We did not quantify the reduction in pollutants such as NOx, SOx, and particulate matter, which are released when fossil fuels are burned for space heating. We also refrained from estimating the global warming impacts of refrigerant leaks associated with the use of heat pumps, which is addressed by our Improve Refrigerant Management solution, or natural gas leaks associated with the use of fossil fuels for heating.
Table 1. Effectiveness at reducing emissions from space heating.
Unit: t CO₂‑eq /heat pump/yr, 100-yr basis
| mean | 0.95 |
A residential air-source heat pump has a mean initial installed cost of US$6,800 and an estimated US$540/yr operational cost for heating. Over a 15-yr lifespan, this results in a net cost of US$990/yr. A heat pump generally replaces both a heating and cooling system with a combined mean installed cost of US$5,300. Operating a baseline heating system costs US$830/yr (operational cooling cost not included in this analysis). Over a 15-year lifespan, the baseline case has a net cost of US$1,180/yr. This results in a net US$190 savings for households that switch to a heat pump. This translates to US$200 savings/yr/t CO₂‑eq reduced (Table 2).
These values include the average annual cost to operate the equipment for heating and the annualized upfront cost of a heat pump relative to both a heating and cooling system that it replaces. There can be significant variability in the upfront cost of equipment based on the type of heat pump installed, the size of the building, and the climate in which it is designed to operate. The cost to operate the equipment for cooling is assumed to be the same with heat pumps and the air conditioners they replace.
There are significant regional differences in the operational cost of heating systems due to climate, utility rates, and the heating systems in use today. The global average outcomes described here are weighted averages from Europe, Canada, the United States, China, and Japan based on regional heating requirements and existing heating technologies.
Utility cost estimates are from June 2023 (GlobalPetrolPrices, 2023) and may vary substantially over time due to factors such as volatile fossil fuel prices, changing carbon prices, and heat pump incentives. Additional installation costs, such as upgrades to electrical systems, ductwork, or radiators are not included.
Table 2. Cost per heat pump climate impact (2023). Negative values reflect cost savings.
Unit: US$/t CO₂‑eq /heat pump/yr, 100-yr basis
| mean | -200 |
Insufficient data exist to quantify the learning curve for heat pumps.
The cost of installing a heat pump includes both equipment costs and the labor cost of installation. According to the U.S. Energy Information Administration (2023), retail equipment costs are 60–80% of the total installed cost of residential air-source heat pumps (central and ductless).
Equipment costs can decrease with economies of scale and as local markets mature, but may be confounded by technological advances as well as equipment and/or refrigerant regulations that can also increase costs (IEA, 2022). European estimated learning rates for heat pump equipment costs range from 3.3% for ground-source heat pumps (Renaldi et al., 2021) to 18% for air-source heat pumps (Jakob et al., 2020). Ease and cost of installation is a research and development goal for manufacturers (IEA, 2022).
The installed cost is also affected by rising labor costs and projected labor shortages (IEA, 2022). Renaldi et al. (2021) showed negative learning rates for the total installed costs in the United Kingdom due to increasing installation costs: -2.3% and -0.8% for air-source and ground-source heat pumps, respectively.
Heat pump manufacturers are also looking to improve the performance of the technology which may impact learning curves. In North America, the Residential Heat Pump Technology Challenge has supported the development of heat pumps with improved cold climate performance (U.S. Department of Energy [U.S. DOE], 2022).
Speed of action refers to how quickly a climate solution physically affects the atmosphere after it is deployed. This is different from speed of deployment, which is the pace at which solutions are adopted.
At Project Drawdown, we define the speed of action for each climate solution as emergency brake, gradual, or delayed.
Use Heat Pumps is a GRADUAL climate solution. It has a steady, linear impact on the atmosphere. The cumulative effect over time builds as a straight line.
Heat pumps can increase demands for electricity and can therefore increase demand for fossil fuel-based power generation. In areas where power generation relies heavily on fossil fuels, heat pumps may generate more emissions than gas heating systems. As the electricity sector adopts more renewables and phases out fossil fuel-based generation, the emissions impact of heat pumps will decrease. Once a building has been designed or retrofitted to accommodate a heat pump it is likely that new heat pumps will be installed at the end of equipment life, perpetuating the benefit.
Efforts are underway to retrofit buildings by improving the insulation, air-sealing and upgrading windows. When done alongside heat pump adoption, they can reduce the size of heat pump needed and increase total energy, emissions, and cost savings.
As heat pump adoption grows, so too will the manufacture of refrigerants, some of which have high global warming potentials when they escape to the atmosphere. See Deploy Alternate Refrigerants and Improve Refrigerant Management solutions for more on accelerating change in this sector.
Our analysis suggests that 130 million heat pumps for heating are currently in operation primarily based on data in Europe, Canada, the United States, China, and Japan (Table 3). These include both all-electric heat pumps and hybrid heat pumps. The IEA (2023a) estimated that 12% of global space heating demand was met by heat pumps in 2022.
This value is based on market reports and national data sources plus IEA estimates of total GW of installed capacity (2022). To convert installed capacity to the number of heat pumps, we used the median from the range of suggested average capacities (7.5 kW for Europe and North America, 4 kW in Japan and China, 5 kW global average). In Japan, where heat pump units typically heat only one room, we assumed 2.4 units per heat pump (International Renewable Energy Agency, 2022).
Table 3. Current heat pump adoption level (2020-2022).
Unit: Heat pumps in operation
| mean | 130,000,000 |
Our estimates put the average adoption trend at 15 million new all-electric and hybrid heat pumps in operation per year (see Table 4). This analysis is based on product shipment data (used as a proxy for installed heat pumps), market reports, national statistics, and IEA data for growth in installed capacity. For the IEA data (2010–2023), we assume a global average of 5 kW of heat capacity per heat pump unit (IEA, 2024).
Shipment and market analysis reports consistently show growing markets for heat pumps in much of the world (Asahi, 2023; European Heat Pump Association, 2024; IEA, 2024). In the United States, shipments of heat pumps have outnumbered gas furnaces since at least 2022 (Air-Conditioning, Heating, and Refrigeration Institute, 2025).
Table 4. Heat pump adoption trend (2010–2023).
Unit: Heat pumps in operation/yr
| 25th percentile | 12,000,000 |
| mean | 15,000,000 |
| median (50th percentile) | 17,000,000 |
| 75th percentile | 18,000,000 |
Our adoption ceiling is set at 1.200 billion heat pumps for space heating by 2050 (see Table 5), most of which are expected to be in residential buildings. This is based on the IEA’s Net Zero Roadmap projection that heat pumps will represent 6,500 GW of heating capacity globally by 2050, covering 55% of space heating demand (IEA, 2023a, p. 98). Our adoption ceiling assumes all-electric heat pumps cover all space heating demand.
We assumed that average heat pump sizes (capacities) will increase over time as heat pumps cover a greater portion of a building’s heating load and as more commercial buildings with larger heating loads install heat pumps. Using a global average of 10 kW per heat pump, the IEA projections imply 650 million heat pumps will be in operation by 2050 with the technical adoption ceiling for 1,200 million heat pumps if all heating demand were met by heat pumps.
Table 5. Heat pump adoption ceiling: upper limit for adoption level.
Unit: Heat pumps in operation by 2050
| mean | 1,200,000,000 |
We estimate the achievable range for heat pump adoption to be 600–960 million heat pumps in operation by 2050 (see Table 6).
Most existing space heating systems will be replaced at least once between now and 2050 because this equipment typically has lifetimes of 15–30 years (U.S. Energy Information Administration, 2023). Policies that encourage high efficiency heat pumps alongside insulation upgrades have the potential to provide lifetime savings, greater comfort, and energy efficiency benefits (Wilson et al., 2024a). Given the available timelines and potential benefits, near full adoption is technically feasible.
We have set the high achievable heat pump adoption at 80% of the adoption ceiling to account for systems that are difficult to electrify due to very cold climates, policy, economic barriers, and grid constraints. This high achievable value assumes that some systems may be replaced before their end of life to meet climate and/or financial goals.
We have set the low achievable heat pump adoption at 50% of the adoption ceiling. This is roughly consistent with the current adoption trend continuing out to 2050.
Our heat pump units adopted include both all-electric and hybrid heat pumps that also rely on fuels for some heating. This analysis assumes that hybrid heat pumps will become less common with time as fuels are phased out and that all-electric heat pumps will dominate by 2050.
Table 6. Range of achievable adoption levels.
Unit: Heat pumps installed
| Current Adoption | 130,000,000 |
| Achievable – Low | 600,000,000 |
| Achievable – High | 960,000,000 |
| Adoption Ceiling | 1,200,000,000 |
Our estimates show the global impact of existing heat pumps for space heating to be a reduction of 0.12 Gt CO₂‑eq/yr (100- and 20-yr basis) based on current adoption and today’s electricity grid emissions (see Table 7). Because electricity grid emissions are decreasing for each kWh of electricity generated (IEA, 2025), the actual impact will be greater than our estimates when future electricity generation emissions are lower.
For the adoption ceiling, assuming heat pumps supply all of the IEA’s projected global heating demand in 2050 (International Energy Agency, 2023a), 1.1 Gt CO₂‑eq/yr (100- and 20-yr basis) could be avoided per year with today’s electricity grid.
A high end achievable target is 80% of the adoption ceiling, accounting for systems that may continue to use fossil fuels for heating due to factors such as cold climates, economic barriers, and grid constraints. This would result in avoiding 0.91 Gt CO₂‑eq/yr (100- and 20-yr basis) with today’s electricity grid emissions.
A low end achievable target is 50% of the adoption ceiling, roughly equivalent to heat pump adoption continuing at today’s rate. This would result in avoiding 0.57 Gt CO₂‑eq/yr (100- and 20-yr basis) with today’s electricity grid emissions.
Table 7. Climate impact at different levels of heat pump adoption.
Unit: Gt CO₂‑eq/yr, 100-yr basis
| Current Adoption | 0.12 |
| Achievable – Low | 0.57 |
| Achievable – High | 0.91 |
| Adoption Ceiling | 1.1 |
Heatwaves and extreme heat are becoming increasingly significant factors of morbidity and mortality worldwide (Romanello et al., 2024). Some buildings that replace heating systems with heat pumps will gain access to cooling (Congedo et al., 2023; Wilson et al., 2024b; Zhang et al., 2017). This can provide protection from heat stress in regions experiencing increasingly hotter summers (where air conditioning was not previously necessary) and for populations that are vulnerable to heat stress, such as the elderly (Malmquist et al., 2022). Some jurisdictions incentivize heat pumps for this reason. For example, the United Kingdom plans to install 600,000 heat pumps by 2028 (Zahiri & Gupta, 2023) and local climate adaptation plans in Canada recommend the installation of heat pumps to provide space cooling that can mitigate morbidity and mortality during heat waves (Canadian Climate Institute, 2023; City of Vancouver, n.d.). Because exposure to extreme heat is disproportionately higher for minority communities – particularly in urban environments – access to cooling has important implications for environmental justice (Benz & Burney, 2021).
Installing heat pumps can lead to greater household savings on electricity. Research has shown that across the United States, heat pumps can reduce electricity bills for 49 million homes with an average savings of US$350–600 per year, depending on the efficiency of the heat pump (Wilson et al., 2024). An analysis by Wilson et al. (2024a) found that higher efficiency heat pumps could be cost-effective for about 65 million households in the United States. Heat pumps also create jobs (Sovacool et al., 2023). In its post-COVID-19 recovery plan, the IEA (2020) estimated that every US$1 million investment in heat pumps could generate 9.1 new jobs and reduce 0.8 jobs in the fossil fuel industry. About half of the new jobs will be in manufacturing, with the remaining distributed between installation and maintenance.
Burning fossil fuels for heating directly emits health-harming particulates and can generate carbon monoxide. Replacing fossil gas heating with heat pumps can reduce air pollution (Carella & D’Orazio, 2021) and contribute to improving health outcomes (Zhou et al., 2022). A study in China showed that as the power grid moves to incorporate renewable energy, the air quality and health benefits of heat pumps will increasingly outweigh the benefits of gas heaters (Zhou et al., 2022). The risk of carbon monoxide poisoning also decreases in buildings that switch from fuel-burning space heating to heat pumps. In buildings that burn fuels for applications such as space heating, carbon monoxide can pose serious health risks, including poisoning and death (Mattiuzzi and Lippi, 2020).
Heat pumps contain refrigerants that often have high global warming potentials. Refrigerant leaks can occur during installation, operation, and end of life (McDiarmid & Parker, 2024). As more heat pumps are adopted, there is a risk of increased emissions from refrigerant leaks during operation as well as refrigerant release at the end of equipment life. Alternate refrigerants with lower global warming potentials are being phased in due to an international agreement to reduce hydrofluorocarbons, including many refrigerants (Kigali Amendment).
Higher rates of heat pump installation will require upscaling heat pump manufacturing and training, plus certification of skilled labor to install them. Skilled labor shortages are already creating bottlenecks for heat pump adoption in some countries, some of which can be met by reskilling other heating technicians (IEA, 2022).
Advancements in heat pump technology will support the development and adoption of heat pump technology for industrial applications.
The increased adoption of heat pumps will increase the market for alternative refrigerants and refrigerant management.
Alternative refrigerants require design changes (Kim et al., 2020) that may increase the upfront cost of heat pumps.
Heat pumps may compete with alternatives such as fossil fuel-based district heating and cooling systems that lack heat pumps as well as low carbon biofuels.
Adoption of heat pumps for space heating is likely to generate seasonal peaks in power demand during cold days that may require building out extra generating capacity that decrease grid efficiency (Bloess et al., 2018). Heat pumps can compete with electric cars for power during peak times (Van Someren et al., 2021).
heat pump system
CO₂ , CH₄, N₂O, BC
Enhanced grid infrastructure will be required to support widespread building electrification and the greater demand for electricity, especially on cold days when heat pumps are less efficient at moving heat (Cooper et al., 2016). Demand side management, thermal storage, home batteries, bidirectional chargers, and greater adoption of ground-source heat pumps can all help to mitigate this increased demand (Cooper et al., 2016; McDiarmid, 2023).
In general, heat pumps have higher upfront costs relative to fueled alternatives but will save a building owner money over the lifetime of the system. This can create economic barriers to accessing the benefits of heat pumps with low-income homeowners and renters who pay for their utilities being particularly vulnerable to being left behind in the transition (Sandoval et al., 2024). Equity advocates are also concerned that the cost of maintaining gas and other fossil fuel infrastructure may increasingly fall on lower-income building owners who struggle to afford the upfront cost of electrifying with heat pumps (Davis & Hausman, 2022).
Electric heat pumps are generally viewed as the primary strategy for reducing GHG emissions from buildings. The Intergovernmental Panel on Climate Change ([IPCC] 2023) noted that heat pumps drive electrification in buildings and help decrease emissions. The European Commission (2022) claims that heat pumps are an essential way of decreasing reliance on gas in heating while increasing the use of renewable energy in the heating sector. The IEA (2022) reported that heat pumps powered by electricity generated with renewable energy “are the central technology in the global transition to secure and sustainable heating.” The International Renewable Energy Agency ([IRENA] 2024) claimed heat pumps in buildings “will play a crucial role in reducing reliance on fossil fuels.”
In one of the largest scientific reviews on the topic, Gaur et al. (2021) concluded that heat pumps “have the potential to play a substantial role in the transition to low carbon heating,” and noted that emissions impacts of heat pumps are dependent on the type of heat pump technology, their location, and the electricity grid mix. Knobloch et al. (2020) studied 59 world regions and found that electrification of the heating sector via heat pumps will reduce emissions in most world regions where they are adopted.
The results presented in this document summarize findings from 46 reports, reviews and meta-analyses and 13 original studies reflecting current evidence from 30 countries, primarily European countries, Canada, the United States, Japan, and China. We recognize this limited geographic and technology scope creates bias, and hope this work inspires research and data sharing on this topic in underrepresented regions and in the commercial sector.
