Water heaters come in many types—gas, electric, oil, and eco-friendly models—and vary in features and capacity ratings, making it difficult to select the optimal unit for a rental property. Their lifespan is generally 10 to 15 years, requiring periodic replacement.
This article provides a comprehensive overview of the different types and features of water heaters, the characteristics of major manufacturers, how to choose the right unit for condos and apartments, typical replacement costs, and key points to keep in mind when replacing a unit.
What types of water heaters are available?
Water heaters are divided into several types based on fuel source and operating mechanism. Understanding the characteristics of each will help you choose the right one for your property.
Gas water heaters
The most widely used type, running on city gas or propane. Their advantages include durability and strong hot water output, though operating costs can be higher and the unit may produce significant noise. In cold regions, freeze protection for water supply pipes is necessary.
Electric water heaters
Demand has grown alongside the spread of all-electric homes. By heating and storing water during off-peak nighttime hours when electricity rates are lower, utility costs can be reduced. While operating costs are lower than gas, water pressure tends to be weaker, and once the stored hot water is depleted, only cold water will flow.
Eco water heaters
A general term for high-efficiency water heaters, including the electric "Eco Cute," the gas-powered "Eco Jozu," and the oil-based "Eco Feel." The extent of utility savings varies depending on residents' schedules and the size of the unit, so it is important to verify this in advance.
Oil water heaters
Fueled by kerosene, these units tend to have lower operating costs than electric water heaters. They are commonly used in cold regions where winter utility bills can be substantial.
Gas instantaneous water heaters
Compact units designed for kitchen use, with limited output that makes them unsuitable for supplying bath water. They come in two types: primary-side shutoff and secondary-side shutoff.
Bath釜 (bath boilers)
A dedicated water heater that uses gas to heat bathwater directly in the tub. It does not supply hot water to the kitchen or washbasin.
Heat source units
Strictly speaking, these differ from standard water heaters—they use heat from hot water to power underfloor heating systems and bathroom dryers. Units with an integrated hot water supply function, known as "hot water supply heating units," are also available.
What are the differences between water heater function types?
Water heaters also fall into four categories based on functionality. Choose according to the expected profile of your property's tenants.
Hot water supply only
A simple type without a reheating function, ideal for properties where cost control is a priority. If the bathwater cools down, hot water must be added manually.
Auto type
Equipped with a reheating function, this type automatically fills the tub to the set temperature and water level with a single touch. It also features automatic reheating and keep-warm functions, and is straightforward to operate.
Full-auto type
All functions are automated beyond those of the auto type, including automatic cleaning of the reheating pipes, automatic top-up, and automatic heating triggered by bath entry detection. Due to higher installation costs, this type is primarily adopted in higher-grade properties.
High-temperature water supply type
This type warms the bathwater by adding high-temperature water at approximately 80°C, and does not include a reheating function. It is suitable for those prioritizing energy savings, as it avoids unnecessary gas consumption.
What are the characteristics of major water heater manufacturers?
Quality, features, and warranty terms differ by manufacturer. Use the following as a reference when selecting the best brand for your property.
Gas water heater manufacturers
Rinnai holds the top domestic market share and is distinguished by its commitment to quality, with even small components manufactured in Japan. It also offers rich functionality, including Bluetooth-enabled remote controls. Noritz is a veteran in water heater development, with strengths in disaster resilience through distributed production facilities in China and a proprietary quality control system. Paloma, founded in 1911, maintains high quality through an integrated production system.
Eco Cute manufacturers
Hitachi is known for its "Niagara Toughness" series, which handles hard water, and its "Powerful Shower" capable of reaching the third floor. Mitsubishi has received the Energy Saving Award for its pursuit of energy efficiency. Panasonic offers appeal through its proprietary Econavi energy-saving technology and HOME IoT compatibility. Toshiba features silver ion sterilization and deodorization along with a five-year manufacturer warranty. Daikin supports powerful high-pressure hot water supply and hot water delivery during power outages. Corona is the world's first Eco Cute manufacturer and holds proprietary energy-saving technology.
How should a water heater be chosen for a condo or apartment?
When selecting a water heater for a rental property, four key factors are important: installation location, capacity rating, functionality, and energy efficiency.
Choose based on the installable type
If there is no space in the PS (pipe shaft), select a balcony-mounted type (wall-hung or floor-standing). For PS installation, choose from standard installation types, alcove installation types, or door-enclosed types based on the appropriate exhaust method.
Choose the capacity rating based on household size
As a guideline, 16-unit capacity is suitable for one to two occupants, 20-unit capacity for two to three, and 24-unit capacity for families of four or more. Larger capacity units come at a higher price.
Choose the type with the necessary features
If cost is a primary concern, the auto type is a safe choice. For higher-grade properties or family-oriented units, consider adopting the full-auto type.
Consider energy-efficient water heaters
The Eco Jozu improves thermal efficiency by 15% over conventional gas water heaters, enabling savings on gas bills. Consider adopting it for family-type properties or where energy efficiency is a key selling point.
How much does it cost to replace a water heater?
Typical replacement costs range from 100,000 to 300,000 yen, covering the unit price plus installation costs (approximately 50,000 yen). The unit price increases with higher capacity ratings and more advanced features.
Tips for reducing replacement costs
Obtaining quotes from multiple contractors allows you to compare costs while identifying reliable service providers. If the unit is within eight years of use, extending its lifespan through maintenance may be more cost-effective than replacing it outright.
Checking manufacturer warranties
Standard manufacturer warranties are typically one year, though some manufacturers offer their own extended warranty programs. Selecting a manufacturer with a comprehensive warranty can lead to long-term cost savings.
What should be noted when replacing a water heater?
Keep the following points in mind to ensure a smooth water heater replacement.
DIY replacement is strictly prohibited
Installing a water heater requires specialized knowledge and skills. Due to the risk of accidents such as water leaks, gas leaks, and electrical faults, always entrust the work to a licensed professional.
Choose a contractor who can respond immediately
Since a water heater failure directly affects tenants' daily lives, prepare a list of contractor candidates in advance so you can act quickly in an emergency.
Hire a contractor with the required qualifications
Replacing a water heater requires qualifications in gas, plumbing, and electrical work. Verify that the contractor holds credentials such as Interior Pipe Construction Technician, LP Gas Equipment Technician, Second-Class Electrician, and Water Supply Works Supervisor.
Confirm the contractor's warranty and after-service
Some contractors offer their own extended warranties of eight or ten years. Also check the quality of after-sales service, including periodic maintenance offerings.
Confirm that the itemized estimate is transparent
A contractor who provides a detailed breakdown of costs is a trustworthy one. Confirm in advance the possibility of additional work or unexpected charges arising during the project.
Do not forget to notify tenants in advance
Remote control replacement work is carried out inside each unit, requiring the tenant to be present. Provide notification well in advance, especially when replacing units across the entire building simultaneously.
Frequently Asked Questions
How long does a water heater last?
The typical lifespan of a water heater is 10 to 15 years. If the unit is within eight years of use, its life can be extended through maintenance. After ten years, replacement parts may become difficult to obtain, so it is advisable to plan for replacement proactively.
Who bears the cost of water heater replacement in a rental property?
In cases of failure due to natural deterioration, it is generally the landlord (lessor) who bears the cost. Failures caused by tenant negligence may be the tenant's responsibility. It is important to review any special provisions in the lease agreement.
Should I choose the Eco Jozu or the Eco Cute?
The Eco Jozu is suitable for properties that already have gas piping, while the Eco Cute is appropriate for all-electric properties. Initial costs tend to be lower for the Eco Jozu, while running costs tend to be lower for the Eco Cute. Make your decision based on the property's existing equipment and the expected lifestyle of its tenants.
What happens if the wrong capacity rating is chosen?
If the capacity is too low, water temperature may drop or flow may diminish when hot water is used simultaneously at multiple points. Conversely, if it is too high, the unit price will be unnecessarily expensive. It is important to select the appropriate capacity rating based on the household composition of the expected tenants.
