When it comes to choosing the right water heater, efficiency and space-saving design are key factors. Ventless tankless water heaters are gaining popularity for their ability to deliver hot water on demand without the need for extensive installation. In 2025, several models stand out for their performance and technology. Let’s explore the top contenders that could greatly improve your hot water experience. You might find one that perfectly fits your needs.
EXCEL Tankless Gas Water Heater (1.6 GPM Propane LPG)
If you’re living in a small apartment or mobile home and need a reliable hot water solution, the EXCEL Tankless Gas Water Heater is an excellent choice for you. This compact unit measures just 12.8” wide and 18.75” high, making it perfect for tight spaces. With a maximum flow rate of 1.6 GPM, it delivers hot water instantly, operating efficiently even at low water pressure. Its vent-free technology means no flues or ductwork are required, enhancing safety with an automatic shutoff feature. Ideal for kitchens and laundry rooms, it fits seamlessly into your lifestyle without sacrificing performance.
Best For: Those living in small apartments, lofts, or mobile homes seeking an efficient and compact hot water solution.
Pros:
- Vent-free technology eliminates the need for flues or ductwork, simplifying installation.
- Low water pressure startup allows operation with only 2 PSI, making it ideal for rural areas and mobile setups.
- Compact design fits easily in tight spaces, perfect for kitchens and laundry rooms.
Cons:
- Maximum flow rate of 1.6 GPM may not be sufficient for simultaneous use at multiple points.
- Limited maximum temperature of 110°F may not meet all users’ hot water needs.
- Customer rating of 3.7 out of 5 stars indicates mixed user satisfaction.
EcoSmart ECO 11 Electric Tankless Water Heater
The EcoSmart ECO 11 Electric Tankless Water Heater stands out for its compact design and efficient performance, making it the perfect choice for those with limited space who still want reliable hot water. With a power output of 13KW at 240 volts, this unit’s self-modulating technology guarantees you get 99% thermal energy efficiency. It delivers endless hot water at a maximum flow rate of 3.1 gallons per minute while maintaining a consistent temperature. Weighing only 6.5 pounds and measuring just 11.5 x 8 x 3.75 inches, it’s ideal for bathrooms and small sinks, making it a smart, space-saving solution.
Best For: Those seeking an efficient and compact hot water solution for small spaces, such as bathrooms and office breakrooms.
Pros:
- 99% thermal energy efficiency, heating water only when needed.
- Compact design allows installation in tight spaces.
- Endless hot water supply with consistent temperature maintenance.
Cons:
- Limited maximum flow rate may not support multiple high-demand applications simultaneously.
- Ideal only for climates with incoming water temperatures of 67°F and above.
- Requires a 240-volt electrical supply, which may not be available in all locations.
Rheem 18kW 240V Tankless Electric Water Heater, Gray
For those seeking an energy-efficient solution to hot water needs, the Rheem 18kW 240V Tankless Electric Water Heater stands out with its impressive 99.8% efficiency rating. This sleek, gray unit measures just 14.5W x 18.25H inches and weighs only 14.78 pounds, making it 90% smaller than traditional tank heaters. With a flow rate of up to 4.4 GPM and a maximum temperature of 140°F, it adapts to your hot water demands using self-modulation technology. Plus, the external digital control offers precise temperature adjustments. Enjoy significant savings on energy bills while maximizing your space and comfort!
Best For: Those looking for an energy-efficient and space-saving hot water solution for their home.
Pros:
- 99.8% energy efficiency helps reduce monthly water heating costs significantly.
- Compact design allows for versatile installation in various spaces, including under sinks.
- Self-modulation technology ensures optimal performance according to hot water demand.
Cons:
- Requires a 240V electrical connection, which may necessitate electrical upgrades in some homes.
- Initial installation cost can be higher compared to traditional tank heaters.
- Limited flow rate may not be suitable for larger households with simultaneous hot water needs.
Rinnai RX199iN Condensing Smart Sense Tankless Water Heater
Experience the convenience of on-demand hot water with the Rinnai RX199iN Condensing Smart Sense Tankless Water Heater, perfect for homeowners seeking efficiency and reliability. This model operates on natural gas or propane, delivering up to 11.1 GPM, which means you can run seven fixtures simultaneously without a hitch. With a super-high energy efficiency factor of .98, it’s designed to save you money. The Quick Flush feature simplifies maintenance, while the Smart Sense gas control system offers advanced functionality. For ideal installation, it’s best to find a qualified technician through the Rinnai PRO page, ensuring your unit operates flawlessly.
Best For: Homeowners looking for an efficient and reliable on-demand hot water solution that can accommodate multiple fixtures simultaneously.
Pros:
- High efficiency: With a UEF of .98, it helps reduce energy costs.
- Capacity: Provides up to 11.1 GPM, allowing for multiple fixtures to be used at once.
- Smart technology: Equipped with a Smart Sense gas control system and optional WiFi control for convenience.
Cons:
- Professional installation required: It is recommended to have a qualified technician for installation, which may add to the overall cost.
- Control module not included: The WiFi control option requires an additional purchase of the Controlr module.
- Limited to gas: Operates only on natural gas or propane, which may not be suitable for all households.
ORBEK 14kW Tankless Electric Water Heater
Looking for a compact and efficient solution for on-demand hot water? The ORBEK 14kW Tankless Electric Water Heater delivers just that, providing endless hot water in just three seconds. With a flow rate of up to 3.38 GPM, it suits 2-3 points of use simultaneously. Its sleek design saves over 50% space compared to traditional tank heaters. Operating at 240 volts, it boasts high energy efficiency, cutting electricity costs by up to 60%. Safety features like leakage and over-temperature protection guarantee peace of mind. Plus, the LED display makes temperature adjustments easy, and 24/7 customer support is always there for you.
Best For: Homeowners looking for a space-saving, energy-efficient solution for on-demand hot water needs.
Pros:
- High energy efficiency reduces electricity costs by up to 60%.
- Provides endless hot water in just 3 seconds for multiple points of use.
- Compact design saves over 50% space compared to traditional tank heaters.
Cons:
- Requires a 240V/60AMP electrical setup, which may necessitate professional installation.
- Limited to a maximum flow rate of 3.38 GPM, which may not be sufficient for larger households.
- Initial cost may be higher compared to traditional tank water heaters.
Rheem 11kW 240V Tankless Electric Water Heater
The Rheem 11kW 240V Tankless Electric Water Heater stands out with its adjustable digital temperature display, making it an ideal choice for those who value precision in their hot water settings. With an impressive flow rate of up to 2.68 GPM, you’ll enjoy consistent and on-demand hot water for multiple outlets simultaneously. The self-modulating power control guarantees efficient energy use, while the ON/OFF dial control adds convenience. Plus, side 1/2 NPT water connections make installation straightforward. If you’re looking for an efficient, space-saving solution for your hot water needs, this Rheem model is a top contender for your home.
Best For: Homeowners seeking an efficient, on-demand hot water solution for multiple outlets with precise temperature control.
Pros:
- Adjustable digital temperature display allows for precise hot water settings.
- Self-modulating power control enhances energy efficiency during operation.
- Compact design saves space compared to traditional water heaters.
Cons:
- Limited flow rate of 2.68 GPM may not be sufficient for larger households with high simultaneous demand.
- Requires professional installation if you’re not familiar with plumbing and electrical work.
- Electric operation may lead to higher utility bills depending on usage patterns.
SIVUATEK 14kW Tankless Electric Water Heater
For those seeking an efficient and space-saving solution for hot water, the SIVUATEK 14kW Tankless Electric Water Heater stands out with its impressive 99% thermal efficiency. With a compact design measuring just 15.87 x 11.14 x 2.87 inches, it easily fits in tight spaces. This unit delivers instant hot water at a flow rate of 3.3 GPM, perfect for multiple use points. Plus, it cuts water heating costs by up to 60%. Safety features like leakage protection and auto shut-off guarantee reliability, making this heater a smart choice for anyone wanting consistent, on-demand hot water.
Best For: Those looking for an efficient, compact, and reliable solution for instant hot water in homes with limited space.
Pros:
- High Efficiency: Achieves up to 99% thermal efficiency, significantly reducing water heating costs.
- Instant Hot Water: Provides endless hot water at a flow rate of 3.3 GPM, suitable for multiple simultaneous uses.
- Safety Features: Equipped with leakage protection, overheating protection, and auto shut-off for enhanced reliability.
Cons:
- Electrical Requirements: Requires a 60-amp circuit breaker, which may need upgrades in some homes.
- Limited Flow Rate: While efficient, the 3.3 GPM flow rate may not suffice for larger households with multiple high-demand fixtures.
- Installation Complexity: Wall-mounted or under-sink installation may require professional assistance for optimal setup.
ThermoMate Tankless Electric Water Heater for Single Sink Faucet
Compact and efficient, the ThermoMate 3500W Tankless Electric Water Heater is an ideal choice for those who need instant hot water at a single sink faucet. With a sleek design measuring just 6.4W x 7.9H x 2.5D inches, it easily fits in tight spaces. This unit boasts a remarkable 99.8% efficiency and a maximum flow rate of 0.66 GPM, ensuring you get hot water quickly. Its self-modulating technology adjusts energy use based on demand, while safety features like overheat protection guarantee safe operation. Plus, the waterproof design and touch control panel make it user-friendly and reliable.
Best For: Those seeking an efficient and compact water heating solution for a single sink faucet in tight spaces.
Pros:
- Highly efficient with a 99.8% energy efficiency rating, reducing electricity costs.
- Self-modulating technology optimizes energy use based on real-time hot water demand.
- Compact design allows for easy installation in limited spaces, such as under sinks or cabinets.
Cons:
- Limited flow rate of 0.66 GPM may not be sufficient for larger sinks or simultaneous use.
- Requires professional installation due to hardwired setup and specific electrical requirements.
- Only suitable for single sink use, limiting its application in larger households or multiple fixture setups.
Rheem RTEX-24 24kW 240V Electric Tankless Water Heater, Gray
Rheem’s RTEX-24 24kW Electric Tankless Water Heater stands out for homeowners seeking a reliable and efficient solution for their hot water needs. This compact, wall-mounted unit measures just 17.63W x 18.25H x 3.5 inches and delivers a flow rate of 5.9 GPM, ensuring continuous hot water for your entire home. With an impressive efficiency rating of 99.8%, it minimizes standby heat loss and requires no venting. The adjustable temperature control lets you customize heat levels from 80 to 140 degrees Fahrenheit. Plus, its lightweight design makes installation a breeze, as long as you have the proper electrical setup.
Best For: Homeowners looking for an efficient and space-saving solution to provide continuous hot water for their entire household.
Pros:
- Highly efficient with a 99.8% efficiency rating, reducing energy costs.
- Compact design that saves space, being up to 93% smaller than traditional water heaters.
- Adjustable temperature control allows for precise heating adjustments in 1-degree increments.
Cons:
- Requires professional installation and specific electrical setup, which can add to initial costs.
- Performance is affected by ground water temperature, which may limit effectiveness in colder climates.
- Higher upfront cost compared to conventional water heaters, despite long-term savings on energy bills.
Tankless Electric Water Heater 5000W
If you’re looking for an efficient solution to your hot water needs, the ECOTINYMACH Tankless Water Heater Electric 110V is an excellent choice. With 5000W of power, it delivers instant hot water on demand, eliminating any wait time. Its user-friendly design features a remote control and an LED display, making operation effortless. You can also switch between Fahrenheit and Celsius easily. This compact unit, measuring just 5.7 x 2.8 x 8.5 inches, is wall-mounted and rustproof, ensuring durability. Plus, its energy-efficient operation only activates when hot water is needed, saving you money on energy bills.
Best For: Those seeking a compact and energy-efficient solution for instant hot water in their homes or small spaces.
Pros:
- Instant Hot Water: Provides hot water on demand, eliminating wait time.
- Energy Efficient: Operates only when needed, reducing energy consumption and costs.
- User-Friendly Design: Features a remote control and an LED display for easy operation.
Cons:
- Wiring Requirements: Requires specific wiring (6mm²/9AWG) and a minimum 60AMP circuit breaker for installation.
- Limited Output: May not be suitable for larger households with high hot water demands simultaneously.
- Professional Installation Recommended: Consult a licensed electrician for proper installation, which may incur additional costs.
Factors to Consider When Choosing Ventless Tankless Water Heaters
When choosing a ventless tankless water heater, you need to take into account several key factors. Installation requirements, energy efficiency ratings, and flow rate capacity all play an essential role in your decision. Additionally, look into temperature control options and safety features to guarantee you pick the best unit for your needs.
Installation Requirements Overview
While considering a ventless tankless water heater, it’s important to evaluate the installation requirements to confirm compatibility with your space and needs. These heaters typically don’t require flues or ductwork, making installation simpler and reducing costs. Many models function well with low water pressure, starting at just 2 PSI, so they’re ideal for rural locations or inconsistent water supplies. Their compact design allows installation in tight spaces, like small apartments or mobile homes. However, make sure you have the correct electrical or gas connections, like a dedicated circuit breaker for electric units or proper gas lines for propane or natural gas models. Always check local building codes, as some areas may impose specific regulations for ventless gas appliances.
Energy Efficiency Ratings
Energy efficiency ratings play an essential role in selecting the right ventless tankless water heater for your home. These ratings indicate how effectively the unit converts fuel or electricity into usable hot water, often expressed as thermal efficiency percentages. Many models boast impressive ratings of up to 99%, meaning they use almost all the energy consumed to heat water. When evaluating options, pay attention to the Uniform Energy Factor (UEF), which measures energy consumption relative to output. Efficient heaters greatly reduce water heating costs by only using energy when hot water is needed, eliminating standby heat loss seen in traditional tank heaters. Remember, factors like installation environment and incoming water temperature can also impact overall energy efficiency.
Flow Rate Capacity
Choosing the right ventless tankless water heater means considering various factors, and flow rate capacity is one of the most significant. Measured in gallons per minute (GPM), flow rate tells you how much hot water your unit can deliver at any moment. If you need to use multiple fixtures at once, opt for a higher GPM rating. For instance, a unit with 1.6 GPM suits single-point applications, while those exceeding 4 GPM can support several fixtures simultaneously. It’s essential to match this capacity with your household’s needs, as factors like climate and incoming water temperature can impact performance. Assess your peak hot water demand—like simultaneous showers or laundry—to select a heater that meets your flow rate requirements effectively.
Temperature Control Options
When it comes to ventless tankless water heaters, temperature control options play a crucial role in ensuring you get the hot water you need at just the right temperature. Many models feature adjustable digital controls, allowing you to set your desired water temperature with precision, often within ±1°F increments. Self-modulating technology helps maintain a consistent temperature by automatically adjusting the heating output based on your water demand, enhancing energy efficiency. You’ll find that some units can reach temperatures up to 140°F, catering to various household needs. Advanced models even come with LED displays for real-time temperature monitoring, making it easy for you to adjust settings and achieve peak performance whenever you need hot water.
Safety Features Importance**
While selecting a ventless tankless water heater, it’s vital to prioritize safety features that protect you and your home. Look for models with an Oxygen Depletion Safety shutoff (ODS), which prevents dangerous gas buildup in enclosed spaces. Automatic shutoff mechanisms, like a 20-minute timer, enhance safety during operation. Guarantee the unit has a magnetic water flow sensor to operate safely under low water pressure, which is common in many areas. Additionally, check for safety certifications like ETL or UL, indicating rigorous testing for safety standards. Over-temperature protection and dry-heating prevention features are essential to avoid overheating and potential fire hazards. Prioritizing these features guarantees a safe and reliable heating solution.
