Tankless water heaters provide on-demand hot water without the bulky tank, offering efficiency and space savings. The best models balance performance, energy use, and ease of installation, but tradeoffs include higher upfront costs or limited flow rates. The top pick for overall performance is the Rinnai RX160iN, praised for its reliability and smart features. For those on a budget, electric models like the Rheem 8kW offer simple, affordable solutions, but may struggle with high demand. Continue reading to see a detailed breakdown of the best options and what makes each one unique.
Get the latest gadgets delivered free — and shop member deals
- Fast, free delivery on millions of items
- Access to Prime Big Deal Days deals on October 6–7
- Prime Video, Amazon Music and more included
Complete the kit
Key Takeaways
- High-capacity gas models like the Rinnai RX160iN excel for large households with high hot water demand.
- Electric options are more affordable and easier to install but often have limited flow rates suitable for smaller homes or specific appliances.
- WiFi-enabled models such as the Westinghouse units add smart control but come at a higher price point.
- Energy efficiency varies significantly; condensing gas models tend to save more over time despite higher initial costs.
- Size and installation complexity are key considerations—compact models suit small spaces but may offer lower performance.
| Rheem 8kW Multi Fixture Tankless Electric Water Heater – 240V |  | Best for Compact Spaces and Light Usage | Power: 8kW | Voltage: 240V | Flow Rate: up to 1.95 GPM | VIEW ON AMAZON | See Our Full Breakdown |
| Westinghouse 11kW Electric Tankless Water Heater, 240V, WiFi, Gray |  | Best for Smart Home Integration and Moderate Hot Water Needs | Power Source: Hard Wiring Required | Special Features: 3s Instant Heating, WiFi, Voice Control | Wattage: 11 KW | VIEW ON AMAZON | See Our Full Breakdown |
| Westinghouse 14kW Tankless Electric Water Heater, 240V, WiFi, ETL Certified, Gray | | Best for Higher Capacity and Smart Home Compatibility | Power: 14 KW | Voltage: 240V | Flow Rate: 3.4 GPM | VIEW ON AMAZON | See Our Full Breakdown |
| Rinnai RX160iN Condensing Smart Sense Tankless Water Heater |  | Best for Large Homes and Whole-House Hot Water | Flow Rate: up to 9 GPM | Fuel Type: Propane or Natural Gas | Efficiency: UEF .97 | VIEW ON AMAZON | See Our Full Breakdown |
| Rheem RTGH Series 8.4 GPM Natural Gas Tankless Water Heater |  | Best for Whole-House High Demand and Energy Efficiency | Flow Rate: 8.4 GPM | BTUs: 157,000 | Efficiency: Super High Efficiency | VIEW ON AMAZON | See Our Full Breakdown |
| Tankless Electric Water Heater, 3000W, 110V, Digital Display, Compact & Wall-Mounted |  | Best Compact Model for Limited Spaces | Power: 3000W | Voltage: 110V | Maximum Temperature: 131°F | VIEW ON AMAZON | See Our Full Breakdown |
| 110V 3000W Tankless Electric Water Heater with Digital Display for Kitchen and More |  | Best for Precise Temperature Control and Energy Efficiency | Power Source: AC | Wattage: 3000W | Voltage: 110V | VIEW ON AMAZON | See Our Full Breakdown |
| 110V Tankless Electric Water Heater, 3000W, Instant Hot Water with Digital Display for Kitchen and Bathroom |  | Best for Safety and Versatility in Small Spaces | Power: 3000W | Voltage: 110V | Maximum Temperature: 131°F | VIEW ON AMAZON | See Our Full Breakdown |
| tankless water heater | Flow Rate | Voltage | Maximum Temperature | Power |
|---|---|---|---|---|
| Rheem 8kW Multi Fixture Tankle | up to 1.95 GPM | 240V | — | 8kW |
| Westinghouse 11kW Electric Tan | 2.56 GPM | — | 140 °F | — |
| Westinghouse 14kW Tankless Ele | 3.4 GPM | 240V | 140°F | 14 KW |
| Rinnai RX160iN Condensing Smar | up to 9 GPM | — | — | — |
| Rheem RTGH Series 8.4 GPM Natu | 8.4 GPM | — | — | — |
| Tankless Electric Water Heater | — | 110V | 131°F | 3000W |
| 110V 3000W Tankless Electric W | 0.45 GPM | 110V | 131°F | — |
| 110V Tankless Electric Water H | 0.3 GPM | 110V | 131°F | 3000W |
More Details on Our Top Picks
Rheem 8kW Multi Fixture Tankless Electric Water Heater – 240V
This Rheem model stands out for its space-saving design and energy-efficient operation, making it ideal for small apartments or secondary bathrooms. Compared with larger units like the Rheem RTGH Series, it offers a modest flow rate of just 1.95 GPM, limiting its capacity for multiple fixtures. Its simple digital thermostat provides precise temperature control, but it requires professional installation due to its specific electrical needs. The limited flow rate and lack of smart features make it less suited for high-demand homes. Still, for single fixture use or light household needs, this model offers reliable hot water without taking up much space.
Pros:- Space-saving compact design
- Energy-efficient, heats water only on demand
- Digital thermostatic temperature controls
Cons:- Requires professional installation and specific electrical setup
- Limited flow rate restricts multiple fixture use
Best for: Single fixture applications, small apartments, or secondary bathrooms needing limited hot water
Not ideal for: Large households or multiple simultaneous water demands, due to its low flow rate
- Power:8kW
- Voltage:240V
- Flow Rate:up to 1.95 GPM
- Temperature Range:80°F – 140°F
- Warranty:5-Year Leak, 1-Year Parts
Our verdict“This model is best suited for small spaces with light water demand and low capacity needs.”
Westinghouse 11kW Electric Tankless Water Heater, 240V, WiFi, Gray
This Westinghouse model enhances convenience with its smart WiFi controls and compact wall-mount design, making it a good choice for tech-savvy users. Its 11 KW power output delivers hot water in just 3 seconds, providing a noticeable upgrade over the Rheem 8kW model, but it still has a flow rate of only 2.56 GPM, which could be limiting in multi-outlet scenarios. Unlike the Rheem, this unit offers voice control and remote temperature management, adding significant convenience. However, it demands a dedicated 60A double-pole breaker and professional electrical installation, which can add to setup complexity. It’s a great fit for those wanting smart features and moderate hot water volume.
Pros:- Provides instant hot water within 3 seconds
- Smart WiFi control compatible with Alexa and Google Home
- Compact wall-mount design saves space
Cons:- Requires dedicated 60A double-pole breaker and specific wiring
- Flow rate may be insufficient for multiple simultaneous outlets
Best for: Homeowners seeking smart controls and reliable instant hot water for small to medium households
Not ideal for: Large families or multiple simultaneous water outlets, because of flow rate limitations
- Power Source:Hard Wiring Required
- Special Features:3s Instant Heating, WiFi, Voice Control
- Wattage:11 KW
- Flow Rate:2.56 GPM
- Maximum Temperature:140 °F
Our verdict“Ideal for tech-savvy users wanting smart features and moderate hot water capacity in small spaces.”
Westinghouse 14kW Tankless Electric Water Heater, 240V, WiFi, ETL Certified, Gray
This 14kW Westinghouse unit offers a significant boost in flow rate at 3.4 GPM, making it suitable for small families or homes with multiple water points. It shares similarities with the 11kW model but supports more simultaneous outlets, though it still requires a dedicated 60A breaker and professional installation. Its WiFi features and ETL certification mirror the 11kW’s convenience and safety, but the higher power demand means more complex wiring. Compared to the Rheem 8kW, it supports greater flow and multiple fixtures, but it isn’t ideal for larger households or high-demand scenarios where even higher capacity models are necessary.
Pros:- Provides hot water in 3 seconds
- Supports multiple water points simultaneously
- Smart WiFi control and safety certified
Cons:- Requires dedicated 60A double-pole breaker and 6 AWG wiring
- Installation complexity may be high for DIYers
Best for: Small households needing increased flow and smart control features
Not ideal for: Large households or multiple bathrooms with high simultaneous demand, due to flow rate limits
- Power:14 KW
- Voltage:240V
- Flow Rate:3.4 GPM
- Maximum Temperature:140°F
- Certifications:ETL
Our verdict“Suitable for small households seeking higher flow rates and smart features, with professional installation recommended.”
Rinnai RX160iN Condensing Smart Sense Tankless Water Heater
The Rinnai RX160iN stands apart for its high flow rate of up to 9 GPM, making it suitable for large households or homes with multiple bathrooms. Its energy-efficient condensing technology ensures lower operating costs, and its flexible indoor or outdoor installation options provide added convenience. While it offers excellent capacity, it requires professional installation, venting, and the Wi-Fi control system is sold separately, adding to the cost. Compared to the Westinghouse models, it provides a much higher flow rate, but at a higher initial investment and installation complexity. This model targets larger families that demand continuous hot water without compromise.
Pros:- Supports up to 9 GPM of hot water
- High energy efficiency with condensing technology
- Indoor or outdoor installation flexibility
Cons:- Requires professional installation and venting
- Wi-Fi control module sold separately
Best for: Large households or homes with multiple bathrooms needing reliable, high-volume hot water
Not ideal for: Small homes or users with limited space and lower hot water demand, due to its size and cost
- Flow Rate:up to 9 GPM
- Fuel Type:Propane or Natural Gas
- Efficiency:UEF .97
- Installation Options:Indoor or Outdoor
- Warranty:15-year heat exchanger
Our verdict“Best suited for large homes needing dependable, high-capacity hot water with energy savings in mind.”
Rheem RTGH Series 8.4 GPM Natural Gas Tankless Water Heater
The Rheem RTGH Series excels in delivering continuous hot water for large households, with a flow rate of 8.4 GPM and high efficiency thanks to condensing technology. Its 157,000 BTUs make it capable of supporting multiple bathrooms simultaneously, making it a strong choice for bigger families. Compared to electric models like the Westinghouse, it offers greater capacity and the benefit of natural gas fuel, which often results in lower operating costs. However, it does require venting, professional installation, and space for mounting, which adds to upfront costs. This model is ideal when high volume and energy savings are priorities, but it’s less suited for small homes or spaces where venting isn’t feasible.
Pros:- Supports continuous hot water for large households
- High efficiency reduces operational costs
- Compact wall-mounted design saves space
Cons:- Requires venting and dedicated space for installation
- Higher upfront cost compared to tank systems
Best for: Large households or multi-bathroom homes needing reliable, high-capacity hot water with energy savings
Not ideal for: Small homes or users seeking electric solutions due to venting or installation complexity
- Flow Rate:8.4 GPM
- BTUs:157,000
- Efficiency:Super High Efficiency
- Power Source:Natural Gas
- Warranty:15-year heat exchanger
Our verdict“A solid choice for large families seeking high capacity, efficiency, and reliable hot water supply.”
Tankless Electric Water Heater, 3000W, 110V, Digital Display, Compact & Wall-Mounted
This model excels in tight spaces where installing larger units isn’t feasible, thanks to its ultra-compact design and wall-mounted setup. Compared with the other two, it offers a slightly lower flow rate of 0.3 GPM, making it ideal for small sinks or single fixtures rather than showers. Its high efficiency (98%) and safety features add reliability, but the limited flow restricts its use in high-demand scenarios. The digital LED display simplifies temperature adjustments, which is a plus for users seeking straightforward operation. However, its vertical-only installation and flow rate limitations mean it’s not suited for larger households or simultaneous use.
Pros:- Ultra-compact, space-saving wall-mounted design
- High thermal efficiency and safety protections
- Easy installation with standard fittings
Cons:- Limited flow rate of 0.3 GPM restricts use to small fixtures
- Vertical installation only, no horizontal option
Best for: Apartment dwellers or RV owners needing reliable hot water for sinks or small appliances.
Not ideal for: Families expecting to run multiple fixtures at once, especially showers, due to its low flow rate.
- Power:3000W
- Voltage:110V
- Maximum Temperature:131°F
- Efficiency:98%
- Water Flow Rate:0.3 GPM
- Dimensions:4.32″ W x 7.86″ H x 1″ D
Our verdict“This is best suited for users with minimal hot water needs in small, confined spaces.”
110V 3000W Tankless Electric Water Heater with Digital Display for Kitchen and More
This pick stands out for its precise temperature control and user-friendly digital display, making it ideal for kitchen and bathroom applications where temperature consistency matters. Compared to the smaller unit, it offers a larger flow rate of 0.45 GPM, suitable for small to medium fixtures, but still not enough for multiple simultaneous showers. Its high efficiency (98%) and safety features like waterproof and leakage protections enhance reliability. Installation is straightforward with pre-drilled holes, but the unit’s horizontal mounting is not permitted, which could limit placement options in tight spaces. Overall, it provides a good balance of performance and safety for single fixture use.
Pros:- Instant heating with precise temperature control
- Compact, space-efficient wall-mount design
- High energy efficiency with safety protections
Cons:- Cannot support multiple fixtures at once
- Horizontal installation not allowed
Best for: Homeowners or RV users needing reliable, precise hot water for sinks and small appliances.
Not ideal for: Larger households or those expecting to run multiple fixtures simultaneously, due to flow constraints.
- Power Source:AC
- Wattage:3000W
- Voltage:110V
- Flow Rate:0.45 GPM
- Maximum Temperature:131°F
- Dimensions:4.5″W x 7.7″H
- Weight:2.4 pounds
Our verdict“This model is ideal for users prioritizing precise temperature control in smaller-scale hot water needs.”
110V Tankless Electric Water Heater, 3000W, Instant Hot Water with Digital Display for Kitchen and Bathroom
This model emphasizes safety, with features like waterproofing (IPX4), leakage, and dry combustion protections, making it suitable for outdoor or humid environments. Compared to the other two, it offers a slightly similar flow rate of 0.3 GPM but includes stainless steel and ABS materials for enhanced durability. Its digital display provides clear temperature monitoring, and installation is simplified through pre-drilled holes. However, like the others, it’s not designed for multiple fixture use at once and requires vertical installation only. This unit is particularly well-suited for users who need reliable, safe hot water in challenging environments or outdoor setups.
Pros:- Enhanced safety protections including waterproofing and leakage safeguards
- Durable stainless steel and ABS construction
- Easy installation with pre-fabricated holes
Cons:- Limited flow rate of 0.3 GPM restricts use to small fixtures
- Vertical installation only, no horizontal mounting option
Best for: Outdoor enthusiasts or those installing in humid spaces requiring extra safety features.
Not ideal for: Large households or multiple simultaneous fixture needs, due to flow and capacity limits.
- Power:3000W
- Voltage:110V
- Maximum Temperature:131°F
- Flow Rate:0.3 GPM
- Material:Stainless Steel and ABS
- Protection Features:Dry combustion, leakage, waterproof
Our verdict“This unit is best for users needing extra safety and durability in outdoor or humid environments with minimal hot water demands.”
How We Picked
Our evaluation focused on performance, energy efficiency, ease of installation, build quality, and overall value. We prioritized models that deliver reliable hot water at various flow rates, ensuring they can meet typical household or commercial demands. Cost was also a factor, from initial purchase price to ongoing energy savings. We examined user reviews, technical specifications, and certifications to determine durability and safety. The final rankings reflect a balance of these elements, highlighting models suited for different budgets and needs.
Factors to Consider When Choosing Tankless Water Heaters
Choosing the right tankless water heater involves understanding your household’s hot water needs, available space, and budget. Not all models are created equal, and some tradeoffs are unavoidable—higher capacity units cost more but offer greater reliability under heavy use. Carefully considering these factors can ensure you select a unit that provides consistent hot water without excess cost or complexity.
Flow Rate and Capacity
The most important factor is how much hot water your household needs at peak times. Larger families or homes with multiple bathrooms require higher flow rates, often measured in gallons per minute (GPM). Investing in a unit with insufficient capacity can lead to cold showers, while overestimating needs may result in unnecessary expense. Always match the heater’s output to your typical usage to avoid disappointment and wasted money.
Fuel Type and Efficiency
Gas models generally offer higher flow rates and better efficiency for larger households, especially condensing models that extract more heat from exhaust gases. Electric units are more straightforward to install and maintain, making sense for smaller setups or supplementary use. Keep in mind that electric models may struggle with simultaneous high-demand appliances, so choose based on your specific hot water load and energy costs.
Installation Space and Complexity
The size and weight of the unit influence installation options. Compact electric models are ideal for tight spaces like closets or small utility rooms. Gas units often require venting and more complex setup, which can add to installation costs. Consider your available space and whether professional help is necessary, especially for gas models with venting and gas line requirements.
Cost and Long-Term Savings
While initial costs vary widely, evaluating the long-term savings from energy efficiency is crucial. Condensing gas models, despite their higher upfront price, typically reduce energy bills over time. Electric models tend to be less costly initially but may incur higher electricity costs depending on local rates. Balancing upfront expense with ongoing savings helps determine the best investment for your home.
Smart Features and Controls
WiFi-enabled models like the Westinghouse units add convenience with remote control and diagnostics, which can help with troubleshooting and maintenance. However, these features come with added cost and complexity. Decide whether remote management is a priority for you or if a simple, no-frills unit better suits your needs. For tech-savvy users, smart controls can enhance overall satisfaction and efficiency.
Frequently Asked Questions
Can I replace my traditional tank water heater with a tankless model?
Replacing a tank water heater with a tankless unit is common, but it requires careful planning. You need to ensure your existing gas line or electrical capacity can support the new unit’s demands. Additionally, installation may involve modifications like venting or new wiring, which can add to costs. Overall, it’s a feasible upgrade for most homes, but consulting a professional helps avoid surprises and ensures compatibility.
How much does a tankless water heater cost to install?
Installation costs vary based on fuel type, complexity, and location. Electric units are generally easier and cheaper to install, often under $1,000 including labor. Gas models, especially high-capacity condensing units, can cost $2,000 or more due to venting, gas line upgrades, and more complex setup. Budgeting for professional installation is wise to ensure safety and proper operation, regardless of the model.
Are electric tankless water heaters suitable for large households?
Electric models tend to have lower flow rates, typically around 2-3 GPM, making them better suited for small households or specific appliances like sinks and dishwashers. For larger families with multiple bathrooms, gas or higher-capacity electric models are more reliable. Always match the unit’s capacity to your household’s peak hot water demand to avoid issues like cold showers.
What maintenance do tankless water heaters require?
Tankless water heaters require regular flushing to prevent mineral buildup, especially in areas with hard water. Annual maintenance checks for gas models include vent inspection and filter cleaning. Electric models are generally simpler to maintain but still benefit from periodic cleaning of filters and checking for corrosion or leaks. Proper maintenance extends the lifespan and keeps performance consistent.
Is a tankless water heater more energy-efficient than a traditional tank model?
Yes, tankless units typically consume less energy because they only heat water on demand, reducing standby heat loss common with tank models. Condensing gas models are especially efficient, extracting maximum heat from exhaust gases. However, the efficiency gain depends on correct sizing and usage patterns; overtaxed units may lose efficiency or struggle to meet demand, so sizing correctly is key.
Conclusion
For households seeking the best overall balance of capacity, efficiency, and smart features, the Rinnai RX160iN stands out as a reliable premium choice. Budget-conscious buyers or small households will find electric options like the Rheem 8kW or compact models a sensible fit, offering straightforward installation and decent performance. Larger families or those with high hot water demands should consider high-capacity gas models, despite their higher initial cost and installation complexity. Beginners and those replacing existing units should prioritize models with simple setup and proven reliability, while tech enthusiasts may prefer units with smart controls. Ultimately, your choice depends on your specific household needs, space, and budget constraints.
Fall Picks
fall essentials
As an affiliate, we earn on qualifying purchases.
