In an apartment, every square foot counts. You want comfort, efficiency, and reliability without giving up valuable space. Hot water is one of those everyday essentials — for showers, cooking, cleaning, and laundry — but a bulky storage water heater can take up far too much room and waste energy reheating water you are not even using. A tankless water heater is the modern solution. It heats water only when you need it, frees up space, and can help reduce utility bills.
In this guide, you will find our top picks for the best tankless water heaters for apartment living in 2025, followed by a complete buying guide covering what to look for, installation tips, and maintenance advice.
Top Tankless Water Heater Picks for Apartments
1. Stiebel Eltron Tempra Plus 24
This electric model is one of the most popular choices for apartments because it is quiet, sleek, and provides steady hot water even when more than one tap is in use. The advanced flow control technology automatically adjusts the water flow to maintain your chosen temperature.
- Best for: Apartments where noise control matters
- Pros: Silent operation, precise temperature control, modern design
- Cons: Higher price than basic electric models
2. EcoSmart ECO 27 Electric Tankless Water Heater
The EcoSmart ECO 27 is ideal for apartments that rely on electricity rather than gas. It can deliver up to 6.5 GPM in warm climates (less in colder areas) and has a compact size that fits easily in small closets or under counters. The digital temperature control lets you adjust settings in one-degree increments.
- Best for: All-electric apartments
- Pros: Space-saving, energy-efficient, adjustable temperature
- Cons: Requires a high-capacity electrical panel
3. Rheem RTEX-18 Electric Tankless Water Heater
The Rheem RTEX-18 offers a balance of performance and affordability. It provides a flow rate suitable for one bathroom apartments and is easy to install in tight spaces. The copper immersion heating elements ensure quick water heating and easy replacement when needed.
- Best for: Small to medium apartments
- Pros: Affordable, easy installation, responsive heating
- Cons: Not ideal for multiple simultaneous uses
4. Rinnai V65iN Indoor Tankless Water Heater
If your apartment has access to natural gas, the Rinnai V65iN offers powerful performance with up to 6.5 GPM. It is compact for a gas unit and features precise temperature control. Direct venting makes it safe for indoor installation in multi-family buildings, provided building rules allow it.
- Best for: Apartments with natural gas service
- Pros: High flow rate, reliable brand, efficient gas heating
- Cons: Requires professional gas and vent installation
5. Bosch Tronic 3000T Electric Mini-Tank
While technically a mini-tank rather than a full tankless system, the Bosch Tronic 3000T is worth mentioning for apartments that need quick, point-of-use hot water without a full installation. It is compact, wall-mountable, and ideal for supplementing a central water system.
- Best for: Point-of-use applications like kitchen sinks
- Pros: Ultra-compact, easy to install, affordable
- Cons: Limited capacity, not for whole-apartment use
Why a Tankless Water Heater Works Well in Apartments
Traditional water heaters store hot water in a tank and keep reheating it to maintain the temperature, even when you are not using it. This wastes space and energy. A tankless water heater heats water on demand, offering several benefits for apartment living:
- Space savings: Wall-mounted design frees up valuable floor area
- Energy efficiency: Only heats water when needed
- Continuous hot water: As long as water and power or gas are available
- Reduced risk of leaks: No large tank that can burst
How to Choose the Right Tankless Water Heater for Your Apartment
Fuel Type
If your apartment has natural gas service, a gas unit can offer higher flow rates. If not, electric models are the way to go. Electric units are generally easier to install in apartments but require adequate electrical panel capacity.
Flow Rate (GPM)
For a one-bathroom apartment, a unit with 3–4 GPM is usually enough. If you have two bathrooms or plan to run multiple fixtures at once, aim for 5–7 GPM.
Size and Installation Location
Measure the available space before buying. Many tankless units fit into closets or utility rooms, but they need proper clearance for safety and maintenance.
Temperature Control
Digital controls give you more precise settings and help prevent temperature fluctuations when multiple fixtures are in use.
Noise Level
If the heater will be installed close to living or sleeping areas, choose a quieter model to avoid disturbance.
Installation Tips for Apartments
- Check building and HOA rules before purchasing
- Hire a licensed professional for installation to meet safety codes
- Ensure proper venting for gas models
- For electric models, verify panel and breaker capacity
- Pick an accessible location for easy maintenance
Maintenance Advice
Tankless water heaters require less upkeep than storage tanks but still benefit from regular maintenance:
- Flush the unit annually to prevent mineral buildup
- Clean inlet water filters periodically
- Inspect connections for leaks
- For gas models, check venting and burners annually
Conclusion
The right tankless water heater for your apartment will depend on your fuel source, space, and water usage. The Stiebel Eltron Tempra Plus 24 offers top-tier performance and quiet operation, while the EcoSmart ECO 27 is a solid electric choice for larger needs. The Rheem RTEX-18 balances cost and performance for smaller apartments, and the Rinnai V65iN is a strong option if you have natural gas service. For point-of-use needs, the Bosch Tronic 3000T is a compact, affordable solution.
With the right model, you can enjoy endless hot water, more space, and improved efficiency — making your apartment living more comfortable and convenient.