[Report] Turning On the AC Heats Up Hot Water... 'Electrification of Heating' Put to the Test in a Jeju Home

Integrated Cooling, Heating, and Hot Water
with a Single Outdoor Unit

Summer Demonstration COP of 4.1:
Fourfold Heat Production from One Unit of Electricity

Samsung Electronics Planning Energy Services
with Integrated Solar Power an

Paek Soonjae, a researcher in the Home Appliance Electronics Division at Samsung Electronics, is explaining the outdoor unit of the "All-in-One EHS Heat Pump" at a house in Donam-dong, Jeju.

On September 14, at a detached house in Donam-dong, Jeju City, a black outdoor unit placed beneath a persimmon tree was noticeably larger than a typical air conditioner outdoor unit—about 1.5 times the size. However, this single outdoor unit can not only serve four air conditioning indoor units installed inside the house, but can also provide underfloor heating and hot water supply.

Since June, Jeju Province and Samsung Electronics have been conducting performance demonstrations of the "EHS All-in-One Heat Pump" at this residence. The EHS All-in-One is a heat pump system that combines both an air-to-air method, which cools indoor air using air from outside, and an air-to-water method, which heats water, into a single outdoor unit. Unlike traditional homes, which require separate air conditioners and boilers, this system features a single outdoor unit that provides cooling, heating, and hot water all together.

Inside the demonstration outdoor unit, key components like a compressor, heat exchanger, and various control boards were tightly installed. Paek Soonjae, a researcher on the development team of the Home Appliance Division at Samsung Electronics, explained, “In Korea, it is necessary to provide not only summer cooling but also underfloor heating in winter and year-round hot water. This product implements all three features in a single system, tailored to the domestic housing culture.”

Interior view of the Samsung Electronics EHS heat pump outdoor unit. Photo by Heejong Kang

Producing Hot Water from Recycled Heat During Cooling

The core feature of the EHS All-in-One is that it reuses, instead of discarding, the heat generated during the cooling process. A typical air conditioner releases the heat it absorbs from inside through its outdoor unit into the surroundings. The EHS All-in-One, on the other hand, recovers this heat to heat water for hot water supply. This means that as soon as you turn on the air conditioner, both cooling and hot water production begin simultaneously.

Since the demonstration started, the coefficient of performance (COP) measured during the summer has been about 4.1. COP is an indicator showing how much cooling, heating, or hot water energy a heat pump can produce compared to the electricity consumed. A COP of 4.1 means that, for each unit of electrical energy used, the system leveraged outside air to produce 4.1 units of heat energy. The electric power is primarily used to operate the compressor.

Outdoor unit view of the EHS heat pump installed at the demonstration house in Donam-dong, Jeju. Photo by Heejong Kang

Samsung Electronics analyzed that, between June (when the product was first installed) and September, there was approximately a 20% reduction in energy consumption when operating cooling and hot water production simultaneously, compared to running them separately. However, this figure reflects only the three months of summer operation data collected so far. To properly evaluate the annual economic efficiency and performance, data from the winter heating season—when heating demand is highest—must also be reviewed.

According to Samsung Electronics, the COP is about 4 when the outside temperature is 7 degrees Celsius and drops to about 2.5 at minus 15 degrees Celsius. Due to the nature of heat pumps, which draw heat from outside air, efficiency decreases as the temperature falls. The company explained that, even during a ten-day period last year in Yangpyeong, Gyeonggi Province, when temperatures hovered around minus 15 degrees Celsius, there were no issues with heating efficiency or performance. Samsung Electronics stated that heating is possible even at minus 25 degrees Celsius.

Reduced to Kimchi Refrigerator Size to Target Apartments

Going down the stairs inside the house to the basement revealed an even more complex setup than the outdoor unit. Around the white hydro unit, pipes covered in red and blue insulation extended along the ceiling and walls. Nearby, two separate thermal storage tanks were installed—one for heating, the other for hot water.

The hydro unit uses heat delivered from the outdoor unit to heat water, then sends it to the heating pipes and the hot water thermal storage tank. The hydro unit’s display showed a hot water tank temperature of 46.5 degrees Celsius and a heating set temperature of 24.5 degrees Celsius. As it is currently summer, only cooling and hot water supply are in operation, with underfloor heating turned off.

View of the hydro unit of Samsung Electronics EHS heat pump and the thermal storage tank installed in the underground mechanical room of the demonstration house in Donam-dong, Jeju.

The complex piping and two storage tanks highlight both the strengths and limitations of the standalone demonstration system. Installing this setup in an existing house requires space not only for the outdoor unit but also for the hydro unit, thermal storage tanks, and water pipes. This is especially challenging in apartments—which make up the majority of Korean residences—where it is generally difficult to secure an underground mechanical room, as in the demonstration house. This is why Samsung Electronics is separately developing products specifically for multi-family housing.

Samsung Electronics plans to introduce a "Kitchenfit" product, which combines the hydro unit and thermal storage tank in an all-in-one unit about the size of a kimchi refrigerator. This compact system can be installed next to a refrigerator or in a kitchen cabinet. The company also intends to offer a variety of capacities according to the size of the residence and the demand for heating and hot water.

However, applying the system to existing apartments requires new piping and equipment space, making new apartment constructions, rather than established buildings, the initial target. Incorporating provisions for the outdoor unit, hydro unit, and thermal storage tanks at the apartment design stage helps minimize installation costs and spatial constraints.

Solar Power and ESS Integration..."KRW 0 Electricity Bills Possible"

The demonstration house in Donam-dong is equipped with a 3 kW solar power system. If electricity generated by the solar panels during the day is used to operate the heat pump, it is possible to reduce the amount of electricity purchased from the grid. Samsung Electronics is also preparing a service that integrates home solar, energy storage systems (ESS), and the heat pump into a single system, enabling unified management of household energy production and consumption.

A model of the "All-in-One EHS Heat Pump" exhibited by Samsung Electronics at the "2026 Green Hydrogen Global Forum," which opened on the 15th in Jeju Island. The "Kitchenfit," which integrates the hydro unit and heat storage tank, is displayed alongside the outdoor unit. Photo by Heejong Kang

When electricity rates are low or solar generation is high, electricity can be stored in the ESS, or the thermal storage tank’s water can be preheated; then, stored energy is used during periods of high electricity prices. In the future, if a market system is introduced that allows households to sell surplus electricity to the grid, a model that brings electricity bills close to zero would be possible. However, this is a long-term business model that would require support from ESS prices, time-of-use electric pricing, surplus power trading systems, and solar generation capacity.

The Jeju demonstration house serves as an important testbed to gauge the feasibility of achieving carbon neutrality in Korea. The government has a policy of reducing greenhouse gas emissions by electrifying heating. However, the high price of heat pumps and the structural difficulties of installing them in Korean residences have been pointed out as obstacles.

The Samsung Electronics system installed in the demonstration house costs about 20 million won (including installation). Samsung Electronics emphasized that this is 3 million won less than the estimated 23 million won needed to install a system air conditioner and a separate heat pump.

Nevertheless, it is clear that the price is still burdensome compared to existing boilers. The government will have to provide subsidies to promote heat pump adoption. The government plans to subsidize about 70% of the installation cost. The company also believes that there is room to further lower the price as production volume increases in the future.

This content was produced with the assistance of AI translation services.