Explains Oidaki (bath reheating) in Japanese rental apartments, its water and gas savings, boiler remote controller guide, bath salt cautions, and finding Oidaki units in UR rental housing.
At a glance
- What is Oidaki?
- A system that recirculates and reheats existing bathtub water at the touch of a button
- Utility Savings
- Saves significant water and gas compared to draining and refilling fresh hot water
- Best For
- Families, couples, or individuals who enjoy long, relaxing bath soaks in Japan
What is Oidaki (Bath Reheating)?
When searching for apartments in Japan, one of the most sought-after features is Oidaki (追い炊き / おいだき), which translates to bath reheating. Rather than draining cooled water and refilling the tub with fresh hot water, an Oidaki system recirculates the water in your tub through the water heater to warm it back up at the press of a button.
In Japanese culture, family members often take turns soaking in the same tub of clean bathwater. Having an Oidaki function allows anyone entering after the first person to quickly reheat the bath to their preferred temperature (typically 40°C–42°C).
Key Benefits and Utility Savings
1. Substantial Water Savings
Refilling a standard Japanese bathtub consumes around 200 liters of water. Reheating existing water prevents wasteful water consumption and significantly lowers your monthly water bill.
2. Gas and Energy Efficiency
Modern Japanese water heaters (給湯器) are engineered with high thermal exchange efficiency. Reheating lukewarm water consumes less gas than heating cold tap water from scratch.
3. Automatic Temperature Maintenance
By turning on the "Auto" (自動) or "Warm Keep" (保温) mode on the boiler controller, the system automatically maintains ideal bath temperature for a designated duration.
Japanese Remote Controller Buttons Guide
Bathrooms and kitchens in Japanese apartments feature wall-mounted controllers with the following Japanese labels:
- 追い炊き / 追炊 (Oidaki): Reheats the bathtub water.
- 自動 (Jidou): Fills the tub automatically and keeps it warm.
- たし湯 (Tashi-yu): Adds a small amount of hot water.
- 保温 (Hoon): Maintains the target water temperature.
- 優先 (Yuusen): Switches temperature control priority between kitchen and bath controllers.
Important Usage Precautions
- Check Bath Additives: Bath salts containing sulfur, salt, or milky/oily residues can damage internal copper piping and water level sensors. Always verify that products are labeled "Oidaki-safe" (追い炊き対応).
- Regular Pipe Cleaning: Use specialized Oidaki pipe cleaners (such as "Jabba" / ジャバ) periodically to sanitize internal circulation pipes and keep them free of bacteria.
Finding Oidaki Units in UR Rental Housing
UR rental housing (UR賃貸住宅) has widely upgraded its renovated apartments and newer buildings with modern Oidaki heating systems. You can easily check whether a unit offers Oidaki on Here UR.
Frequently asked questions
What is the difference between Oidaki (reheating) and Tashi-yu (adding hot water)?
Tashi-yu adds new hot water and increases the water level. Oidaki recirculates existing bathtub water through the boiler heater, bringing it back to temperature without raising the water level.
Can I use bath salts with an Oidaki system?
Avoid bath salts containing sulfur, salt, milky sediments, or heavy oils, as they can corrode boiler pipes and clog circulation sensors. Only use bath salts explicitly labeled as Oidaki-safe (追い炊き対応).
Are Oidaki-equipped units available in UR rental housing?
Yes! Renovated UR housing units and newer complexes frequently feature modern Oidaki boiler systems. You can check availability on Here UR.
Compare current vacancies by area
After checking the rules, compare current vacancies and monthly totals in Tokyo, Osaka and Kanagawa.