If you’re living in a small apartment, a tiny house, or simply want a water heater that saves space, a small tankless water heater might be exactly what you need. These compact units offer the convenience of instant hot water on demand, without the need for a large, bulky storage tank. Not only do small tankless models save space, but they’re also more energy-efficient than traditional tank water heaters.
In this guide, we will explore the best small tankless water heaters of 2025, highlighting their features, energy efficiency, and value. Whether you’re looking for a point-of-use model for a sink or a compact solution for your entire home, we’ve rounded up the top choices to help you make an informed decision.
Why Choose a Small Tankless Water Heater?
Small tankless water heaters are perfect for those who are looking to save both space and energy while enjoying a reliable supply of hot water. Here’s why they’re a great choice:
- Space-Saving: Small tankless units are compact and designed to be installed in tight spaces, such as under sinks, in closets, or on the wall, making them perfect for apartments and small homes.
- Endless Hot Water: Unlike traditional tank models that store a finite amount of hot water, tankless units heat water on demand, ensuring you never run out of hot water, no matter how much you use.
- Energy Efficiency: Tankless water heaters only heat water when it’s needed, which helps reduce energy consumption compared to traditional water heaters that constantly keep water hot.
- Longer Lifespan: Tankless units typically last longer than traditional tanks due to their design and fewer components that are prone to wear and tear.
Top 5 Best Small Tankless Water Heaters of 2025
After considering factors like energy efficiency, space requirements, and performance, we’ve compiled a list of the top small tankless water heaters for 2025:
1. EcoSmart ECO 11 Electric Tankless Water Heater
The EcoSmart ECO 11 is a compact and efficient electric tankless water heater that’s ideal for small homes, apartments, or point-of-use applications like sinks and showers. This model is designed to provide hot water on demand, saving both space and energy.
- Capacity: Ideal for 1-2 bathrooms or point-of-use applications
- Energy Efficiency: 99.8% energy efficiency with self-modulating technology
- Flow Rate: 2.6 gallons per minute (GPM) at a 35°F rise
- Warranty: 5-year limited warranty
This electric model is highly efficient and offers consistent hot water for smaller spaces, making it an excellent choice for apartments or homes with low hot water demand.
2. Rinnai V65iN Tankless Water Heater
The Rinnai V65iN is a natural gas-powered tankless water heater that delivers reliable hot water for small to medium homes. It’s compact, efficient, and ideal for homes with limited space but higher water demands.
- Capacity: 6.6 gallons per minute (GPM)
- Fuel Type: Natural gas
- Energy Efficiency: High energy factor (EF) for reduced energy consumption
- Warranty: 12-year limited warranty
The Rinnai V65iN is perfect for medium-sized homes that require hot water for multiple applications at once, such as a bathroom and kitchen. Its compact size and energy-efficient operation make it an ideal choice for those looking to save space and reduce energy costs.
3. Bosch Tronic 3000 4-Gallon Electric Mini-Tank Water Heater
If you’re looking for a small tankless unit for point-of-use installations, the Bosch Tronic 3000 mini-tank water heater is an excellent option. It’s designed to provide instant hot water at a single location, such as a bathroom sink or a small kitchen.
- Capacity: 4 gallons
- Energy Efficiency: Insulated tank for heat retention
- Installation: Can be installed under sinks or in tight spaces
- Warranty: 6-year limited warranty
This mini-tank model is perfect for small homes, apartments, or as a supplemental water heater for specific points of use, offering energy savings and reliable performance.
4. Stiebel Eltron Tempra 24 Plus Tankless Water Heater
The Stiebel Eltron Tempra 24 Plus is a compact tankless water heater that provides energy-efficient hot water on demand. Ideal for smaller homes or apartments, it offers a flow rate that’s sufficient for moderate hot water demand.
- Capacity: Suitable for homes with 1-2 bathrooms
- Energy Efficiency: High energy factor (EF) with advanced temperature control
- Flow Rate: 4.0 GPM at a 35°F rise
- Warranty: 7-year limited warranty
This model is designed for energy-conscious homeowners who want a compact, high-performing water heater that saves both space and energy. The Tempra 24 Plus provides consistent hot water while reducing operational costs.
5. Takagi T-KJr2-IN-NG Tankless Water Heater
The Takagi T-KJr2-IN-NG is a compact, natural gas-powered tankless water heater that is perfect for small to medium homes. It’s designed to provide hot water on demand for homes with lower water usage while maximizing energy savings.
- Capacity: 6.6 gallons per minute (GPM)
- Fuel Type: Natural gas
- Energy Efficiency: High energy factor (EF) for reduced energy consumption
- Warranty: 15-year limited warranty on heat exchanger
This natural gas-powered model offers excellent value and efficiency for small homes or apartments. Its compact design ensures that it can be installed in tight spaces, while its energy-efficient operation helps reduce monthly utility costs.
How to Choose the Best Small Tankless Water Heater
When selecting a small tankless water heater, several factors should be considered to ensure that you choose the best unit for your home:
1. Size and Flow Rate
The size of the water heater and its flow rate (measured in gallons per minute or GPM) are crucial for determining whether it will meet your household’s needs. For small homes or apartments, a unit with a flow rate of 4-6 GPM is typically sufficient.
2. Energy Efficiency
Look for models that are Energy Star rated or have a high energy factor (EF). Tankless water heaters are generally more energy-efficient than traditional tank models, but some are more efficient than others. High-efficiency units will help reduce your long-term energy costs.
3. Fuel Type
Consider the available fuel source for your home. Electric models are easier to install and require no venting, but gas models typically provide higher flow rates and lower operating costs. Choose the model that best suits your household’s needs and energy source.
4. Installation Space
Small tankless water heaters are designed to save space, but it’s still important to ensure that the unit will fit in the desired installation area. Measure the available space before purchasing and check the unit’s dimensions to ensure a proper fit.
Conclusion
Small tankless water heaters offer a great combination of space-saving, energy efficiency, and reliable performance. Whether you need a unit for a small apartment or a point-of-use installation, the top models we’ve reviewed offer excellent value and performance for homes with low to moderate hot water demands.
Ready to upgrade to a tankless solution? Consider one of the top small tankless water heaters we’ve highlighted to enjoy instant hot water, energy savings, and a more efficient use of space in your home.