Korean homes use a ondol (hot-water underfloor heating) system that circulates warm water beneath the floor to heat the entire room. The boiler supplies both this underfloor heating and the hot water you need for showers and washing dishes. You control temperature and functions through a small wall-mounted controller panel, but because the layout differs between manufacturers and models, it can feel confusing at first. Follow the steps below and you will get the hang of it quickly.

If you want to save on gas bills during winter, also check out How to Save on Gas Bills for Your Boiler (Ondol) in Winter. If you want to improve heating efficiency by insulating your windows, read Winter Window Insulation: How to Apply Bubble Wrap (Air Cap).

Figures and deadlines can change with each season, so for the latest information please contact 1345 (Immigration Contact Center, a multilingual hotline for foreigners in Korea) or your local Korea Immigration Service office.

Step-by-Step Overview

  1. 1. Turn the power on

    Press the power button on the wall controller panel to turn the boiler on.

  2. 2. Select a season or mode

    In summer, choose hot-water-only mode; in winter, choose heating-and-hot-water (or heating) mode.

  3. 3. Set the temperature

    Use the up/down buttons or a dial to set the heating temperature or hot-water temperature you want.

  4. 4. Confirm operation

    When the operation LED lights up, the boiler is running normally. It takes about 30 minutes to 1 hour for the floor to feel warm.

  5. 5. Switch modes when going out or sleeping

    When leaving the house, switch to Away mode instead of turning the boiler off completely, to prevent pipes from freezing.

  6. 6. Set a schedule (optional)

    Use the reservation (timer) function to set times for the boiler to turn on and off automatically, saving on heating costs.

Buttons You Should Know (All Brands)

Korean LabelMeaningWhen to Use
전원 (Power)Power on/offTo turn the entire boiler on or off
난방 (Heating)Underfloor heatingTo heat the room in winter
온수 / 온수전용 (Hot Water / Hot Water Only)Hot waterTo use hot water only for showers or dishes (mainly in summer)
외출 (Away)Away modeTo reduce heating to the minimum temperature when you leave the house
예약 (Reservation)Timer/scheduleTo set times for the boiler to turn on and off automatically
실내 / 실온 (Indoor / Room Temp)Room-air-based heatingTo regulate heating based on the air temperature in the room
온돌 (Ondol)Floor-temp-based heatingTo regulate heating based on the floor temperature
꺼짐 (Off)Heating offTo turn off only the heating (mainly in summer)

Rinnai Boilers

Rinnai is one of the most common boiler brands found in Korean homes. The button layout varies slightly by model, so find the type that matches your unit.

Official website: Rinnai Korea

Rinnai Type 1

  • Power (전원): Turns the entire boiler on or off. Also used as a reset button when a problem occurs.
  • Display: Shows the current temperature as a number.
  • Hot Water (온수): Supplies hot water for showers or baths. Press once for low (저), twice for medium (중), three times for high (고).
  • Heating (난방): Adjusts the underfloor heating temperature. Turn the dial left to lower the temperature (저) and right to raise it (고).
  • Away (외출): Switches to Away mode. Keeps heating at the minimum temperature while you are out, preventing frozen pipes.
  • Off (꺼짐): Turns the heating completely off. Used mainly in summer.
  • Reservation (예약): Sets the times for the boiler to turn on and off automatically.
  • Room Temp / Ondol (실온 / 온돌): Chooses whether to regulate heating based on indoor air temperature (실온) or floor temperature (온돌).

Rinnai Type 2

  • Power (전원): Turns the entire boiler on or off.
  • Operation LED (운전 LED): The indicator light stays on while the boiler is running.
  • Hot Water Only (온수전용): Supplies hot water without activating underfloor heating. Used mainly in summer.
  • Heating + Hot Water (난방온수): Supplies both hot water and underfloor heating at the same time. Used mainly in winter.
  • Away (외출): Switches to Away mode.
  • Heating Water Temperature (난방수온도조절): Adjusts the temperature of the water used for underfloor heating. Turn left to lower, right to raise.
  • Hot Water Temperature (온수온도조절): Adjusts the hot water temperature from low (저온) to high (고온).

Rinnai Type 3

  • Hot Water (온수): Supplies hot water. Used in both summer and winter.
  • Hot Water Temperature (온수온도): Press once for low, twice for medium, three times for high.
  • Heating (난방): Activates underfloor heating. Used in winter only.
  • Heating Temperature (난방온도): Adjusts the underfloor heating temperature from low to high.
  • Combustion LED (연소 LED): The indicator light stays on while the boiler is running.
  • Away (외출): Switches to Away mode.
  • Reservation (예약): Sets the start and stop times for the boiler to run automatically.

Kiturami Boilers

Kiturami (귀뚜라미) is one of Korea’s leading boiler brands. Its display shows a lot of information, which can look complicated at first.

Official website: Kiturami Boiler

  • Display: Shows the current state, including current temperature (현재온도), target temperature (희망온도), reservation time (예약), whether the boiler is running (운전), and the selected season (계절).
  • Function Select (기능 선택): Choose from Indoor (실내, room-temperature-based heating), Reservation (예약), or Away (외출). To activate underfloor heating, select Indoor mode.
  • Bath (목욕): Supplies a large amount of hot water at once for a bath or shower.
  • Power (전원): Turns the entire boiler on or off.
  • Operation LED (운전 LED): The indicator light stays on while the boiler is running.
  • Up / Down (올림 / 내림): Raises or lowers the target temperature or setting value for the currently selected function.
  • Season Select (계절선택): Automatically sets an appropriate heating temperature for the current season. Choose from Spring (봄), Summer (여름), Autumn (가을), Early Winter (초겨울), or Winter (겨울).
  • Reservation Setting (예약설정): Sets the start and stop times for the boiler to run automatically.

Navien (경동나비엔) is a boiler brand widely used both in Korea and internationally.

Official website: Kyungdong Navien

  • Power (전원): Turns the entire boiler on or off.
  • Operation LED (운전 LED): The indicator light stays on while the boiler is running.
  • Heating Control (난방조절): Adjusts the underfloor heating temperature. Turn left (-) to lower, right (+) to raise.
  • Away (외출): Switches to Away mode.
  • Off (꺼짐): Turns heating off. Used mainly in summer.
  • Indoor (실내): Regulates heating based on room air temperature. Used in winter.
  • Hot Water Only (온수전용): Supplies hot water without activating underfloor heating. Used mainly in summer.
  • Ondol (온돌): Regulates heating based on floor temperature. Used in winter; works similarly to Indoor mode.
  • Reservation (예약): Sets times for the boiler to run automatically.
  • Hot Water Control (온수조절): Adjusts hot water temperature to low (저), medium (중), or high (고).
  • Power (전원): Turns the entire boiler on or off.
  • Display: Shows indoor temperature (실내온도), heating water temperature (난방수온도), and whether the boiler is running (운전).
  • Hot Water Only (온수전용): Supplies hot water only. Used mainly in summer.
  • Indoor Control (실내조절): Adjusts the target indoor temperature between 10 and 40 degrees Celsius.
  • Away (외출): Switches to Away mode.
  • Heating Water Temperature (난방수온도): Sets the heating water temperature to suit the season. Choose from Summer (여름), Spring/Autumn (봄/가을), or Winter (겨울).
SeasonRecommended Setting
SummerUse Hot Water Only or the hot water button alone. Set heating to Off.
Spring / AutumnKeep hot water on; set heating to a low temperature depending on the weather.
WinterUse Heating + Hot Water or Ondol / Heating mode. Away mode is recommended for long absences.

For how to prepare for cold snaps and sudden temperature drops, see Preparing for Winter Cold Snaps: Cold Weather Alerts, Preventing Frozen Pipes, and Saving on Heating Bills.

What to Do If Something Goes Wrong

If an error occurs or the boiler stops working, first try pressing and holding the power button to reset it. If you smell gas or hear unusual noises, open the windows immediately, turn off the gas valve, and contact the numbers below. If the problem still cannot be resolved, contact the after-sales service center for your brand. Service numbers and hours are subject to change, so please check the official website for the latest information before calling.