The success or failure of the energy transition for carbon neutrality does not hinge on the adoption of any single technology. What matters most is how coherently a nation's energy supply and demand structure is designed. In South Korea, where comprehensive and specific decarbonization policies for thermal energy remain relatively insufficient, devising countermeasures is critically important. The government recently included air-source heat pumps in the renewable energy category and set a deployment target of 3.5 million units by 2035. Heat pumps are one strategy for electrifying heating. They can be considered eco-friendly and a means of decarbonization in that they harness heat from ambient air. However, electricity is an essential input for these systems to operate. The question is how that electricity is generated.
As of 2024, approximately 56.2% of South Korea's power generation still relies on fossil fuels such as coal and liquefied natural gas (LNG), while renewable energy accounts for just 10.5%. The greenhouse gas reduction effect depends on how the electricity powering heat pumps is produced. When the share of fossil fuel generation remains high, there are limits to classifying air-source heat pumps as genuinely renewable energy. From a technical standpoint as well, air-source heat pumps are difficult to regard as well suited to South Korea's climate conditions. Their performance fluctuates significantly depending on outdoor temperature. A synthesis of overseas field studies and domestic analyses shows that when winter outdoor temperatures drop below minus 10 degrees Celsius, the coefficient of performance (COP) falls sharply to below 2.0. This means heating efficiency relative to electricity input deteriorates substantially. It suggests the system is ill-suited to South Korea, which repeatedly experiences cold snaps below minus 10 degrees Celsius every year.
Expanding heat pump adoption could burden not just individual households but also the national power system. Peak electricity demand reached 95.9 GW last year. As the heating sector's dependence on electricity grows, power-intensive industries such as artificial intelligence (AI) data centers and the semiconductor sector are expanding rapidly, necessitating a review from an energy security perspective as well.
The economic burden also cannot be overlooked. According to the Korea Energy Economics Institute, air-source heat pumps cost 11 million to 15 million won ($8,000 to $11,000) to install — more than seven times the 1 million to 2 million won for a gas boiler. With increased electricity consumption, the likelihood of entering the third-tier progressive rate bracket, where charges are 2.5 times higher than the first tier, grows, inevitably expanding household energy cost burdens. There are also considerations from the perspective of the industrial ecosystem. A handful of large corporations already hold a substantial share of the air-source heat pump market. If renewable energy designation is combined with policy support, existing renewable energy industries centered on small and medium-sized enterprises — including geothermal, hydrothermal, and solar thermal — are likely to shrink.
In conclusion, air-source heat pumps can be one option where conditions are met. However, in South Korea's reality of a low renewable energy share in the power mix and high demand volatility during severe cold spells, cases meeting limited conditions should be examined first. Carbon neutrality is not simply a matter of speed but a matter of direction.
Heat pumps should be deployed only in areas meeting certain conditions where the COP is sufficiently high. For the rest, a more realistic and cost-effective policy would be to utilize existing supply networks with nationwide infrastructure already in place. National research and development (R&D) and policy support are needed to supply clean energy — such as biogas, clean hydrogen, and e-methane — through existing city gas pipeline networks.