Imagine stepping into a steaming hot shower, only to be hit with an icy blast mid-lather because your water heater can’t keep up. It’s a frustrating reality for many households relying on outdated tank water heaters. Enter best 10 tankless water heaters, the game-changer delivering endless hot water on demand, saving space, and slashing energy bills by up to 50%. But with countless models flooding the market, picking the right one can feel daunting. This comprehensive guide reviews the best 10 tankless water heaters of 2025, meticulously selected based on current Amazon ratings, customer reviews, and expert insights from trusted sources like Consumer Reports and This Old House. With a detailed comparison table, in-depth reviews, and a tailored buying guide, we’ll empower you to choose the perfect unit for your home’s needs, ensuring no more cold showers or wasted energy.
How We Chose Our Top Picks
To find the best 10 tankless water heaters, we conducted extensive research, analyzing thousands of Amazon reviews, sales data, and third-party evaluations from authoritative sites like Wirecutter, Consumer Reports, and This Old House. Our methodology prioritized:
- Flow Rate (GPM): Ensuring models meet the hot water demands of various household sizes (e.g., 2-5 bathrooms).
- Energy Efficiency (UEF): Focusing on units with a Uniform Energy Factor (UEF) above 0.90 for maximum savings.
- Durability and Warranty: Selecting heaters with 10+ year warranties and proven longevity (15-20 years).
- Customer Feedback: Prioritizing models with at least 4-star Amazon ratings and positive comments on reliability and installation.
- Value for Money: Balancing upfront costs with long-term savings and performance.
We emphasized gas and electric models to suit diverse needs, prioritizing those excelling in hard water areas and cold climates. These picks stand out for their energy savings (up to 50% vs. traditional tanks), compact designs, and high customer satisfaction, making them authoritative choices for informed buyers.
Product Comparison Table
| Product Name | Flow Rate (GPM) | Price Range |
|---|---|---|
| Rinnai RX199iN | 11.0 | $1,474.00 |
| Rheem RTGH-95DVLN | 9.5 | |
| Stiebel Eltron Tempra 36 Plus | 8.0 | $845.00 |
| EcoSmart ECO 36 | 6.0 | $519.99 |
| Takagi T-H3-DV-N | 10.0 | $1,552.89 |
| Noritz NRC66DVNG | 6.6 | $1,322.75 |
| Rheem RETEX-36 | 7.5 | $829.95 |
| EcoSmart ECO 27 | 6.0 | $532.47 |
| Stiebel Eltron Tempra 24 Plus | 5.0 | $529.49 |
| EcoSmart ECO 18 | 4.0 | $207.76 |
Detailed Reviews of the Best Tankless Water Heaters
1. Rinnai RX199iN Condensing Tankless Water Heater
- Compelling Product Description: The Rinnai RX199iN is a premium natural gas tankless water heater designed for large households with high hot water demands. Its 11 GPM flow rate powers up to seven fixtures simultaneously, ensuring no one’s left in the cold during busy mornings. With smart recirculation technology, hot water arrives in seconds, reducing water waste. ENERGY STAR certified with a 0.95 UEF, it’s a leader in efficiency, saving up to 40% on gas bills. Wi-Fi connectivity allows app-based control, making it a tech-savvy choice for modern homes.
- Price: $1,474.00
- Key Features and Benefits:
- 199,000 BTU output for robust heating.
- Smart recirculation with Circ-Logic technology minimizes wait time.
- Wi-Fi-enabled for remote temperature adjustments.
- 15-year heat exchanger warranty, 5-year parts.
- Ultra-low NOx emissions for eco-friendliness.
- Benefits: Saves space (compact at 22.5” x 17.7”), reduces energy costs, and handles multiple simultaneous uses.
- Pros and Cons:
- Pros: Exceptional flow rate, quiet operation, long-lasting with minimal maintenance, eco-friendly.
- Cons: High upfront cost, requires professional installation and PVC venting.
- Amazon Customer Ratings and Reviews: 4.5/5 stars from 250+ reviews. Customers praise its reliability, with comments like, “Handles three showers and a dishwasher with no issues!” Some note complex installation in older homes.
- Why It’s a Good Choice: Rinnai’s reputation for durability and its high flow rate make this a top pick for large families seeking premium performance and energy savings.
- Ideal Use Case or Who Should Buy It: Perfect for households with 4+ bathrooms or high hot water demand, especially in colder climates where groundwater is below 50°F.
2. Rheem RTGH-95DVLN Condensing Tankless Water Heater
- Compelling Product Description: The Rheem RTGH-95DVLN combines affordability and high performance, delivering 9.5 GPM to support medium to large homes. Its EcoNet smart system enables Wi-Fi monitoring, while Hot-start Programming eliminates cold-water bursts. With a 0.93 UEF and low NOx emissions, it’s an eco-conscious choice that cuts gas bills by up to 30%. Its compact design and easy maintenance make it a favorite among homeowners seeking value without sacrificing quality.
- Price:
- Key Features and Benefits:
- 199,900 BTU with modulating gas valve for efficiency.
- EcoNet Wi-Fi for remote diagnostics and control.
- Dual heat exchangers (copper and stainless steel) for durability.
- 12-year heat exchanger warranty, 5-year parts.
- Benefits: Handles four simultaneous fixtures, reduces installation costs with PVC venting.
- Pros and Cons:
- Pros: Cost-effective for features, reliable in cold climates, quiet operation.
- Cons: Venting setup can be complex in non-standard homes, slightly lower flow than Rinnai.
- Amazon Customer Ratings and Reviews: 4.2/5 stars from 300+ reviews. Users love the energy savings, with one saying, “My gas bill dropped significantly!” Some mention venting challenges.
- Why It’s a Good Choice: Offers a balance of performance, efficiency, and affordability, backed by Rheem’s reliable customer support.
- Ideal Use Case or Who Should Buy It: Medium to large homes (3-4 bathrooms) with natural gas access, ideal for budget-conscious buyers prioritizing efficiency.
3. Stiebel Eltron Tempra 36 Plus Electric Tankless Water Heater
- Compelling Product Description: German-engineered for precision, the Stiebel Eltron Tempra 36 Plus is a top-tier electric tankless water heater delivering 8 GPM for medium-sized homes. Its Advanced Flow Control ensures consistent temperatures, even during flow fluctuations, while a 99% efficiency rating maximizes energy savings. With no venting required and silent operation, it’s perfect for all-electric homes seeking a reliable, space-saving solution.
- Price: $845.00
- Key Features and Benefits:
- 36 kW power with self-modulating technology for efficiency.
- Digital thermostat with 1-degree increment adjustments (80-140°F).
- Advanced Flow Control prevents temperature drops.
- 7-year warranty against leaks, 3-year on parts.
- Benefits: No venting needed, easy installation, ultra-quiet.
- Pros and Cons:
- Pros: High efficiency, compact (14.5” x 16.5”), ideal for homes without gas.
- Cons: Requires 300A electrical service, not suited for very large homes.
- Amazon Customer Ratings and Reviews: 4.4/5 stars from 500+ reviews. Customers rave about consistent hot water, with one noting, “Perfect for our three-bathroom home.” Some cite high electrical upgrade costs.
- Why It’s a Good Choice: Its reliability and efficiency make it the best electric option for consistent performance in smaller to medium homes.
- Ideal Use Case or Who Should Buy It: Homes without gas lines, with 2-3 bathrooms, in warmer climates (groundwater >60°F).
4. EcoSmart ECO 36 Electric Tankless Water Heater
- Compelling Product Description: The EcoSmart ECO 36 is a budget-friendly electric tankless water heater designed for medium-sized homes, delivering 6 GPM with exceptional 99% energy efficiency. Its patented self-modulating technology adjusts power usage to demand, minimizing energy waste. Compact and easy to install, it’s a top choice for cost-conscious buyers seeking reliable hot water without the high upfront cost of gas models. Ideal for homes with moderate hot water needs, it offers a sleek design and straightforward operation.
- Price:$519.99
- Key Features and Benefits:
- 36 kW power with self-modulating technology for optimal efficiency.
- Digital temperature control (80-140°F) for precise adjustments.
- Copper and stainless steel components for durability.
- Lifetime warranty for residential use, 5-year limited warranty.
- Benefits: Saves up to 50% on water heating costs, no venting required, fits in tight spaces (14” x 19”).
- Pros and Cons:
- Pros: Affordable, high efficiency, easy to install, ideal for smaller homes.
- Cons: Limited flow rate for larger households, requires 300A electrical service.
- Amazon Customer Ratings and Reviews: 4.3/5 stars from 600+ reviews. Customers appreciate the low cost and performance, with one stating, “Great for our 2-bathroom home, no issues!” Some note electrical upgrades as a hurdle.
- Why It’s a Good Choice: Offers excellent value with high efficiency and a lifetime warranty, perfect for budget-focused buyers.
- Ideal Use Case or Who Should Buy It: Small to medium homes (2-3 bathrooms) without gas lines, in warmer climates where high flow isn’t critical.
5. Takagi T-H3-DV-N Condensing Tankless Water Heater
- Compelling Product Description: The Takagi T-H3-DV-N is a high-performance natural gas tankless water heater delivering 10 GPM, ideal for large homes with heavy hot water demands. Its condensing technology achieves a 0.95 UEF, maximizing energy savings. With durable heat exchangers and easy maintenance, it’s built to last 20+ years. Safety features like freeze protection and surge protection make it reliable in harsh conditions, offering peace of mind for families.
- Price: $1,552.89
- Key Features and Benefits:
- 199,000 BTU with condensing technology for high efficiency.
- Dual heat exchangers (copper and stainless steel) for longevity.
- Built-in freeze and surge protection for reliability.
- 15-year heat exchanger warranty, 5-year parts.
- Benefits: Supports 4-5 simultaneous fixtures, reduces gas bills by 40%.
- Pros and Cons:
- Pros: High flow rate, durable, energy-efficient, great for large homes.
- Cons: Requires professional installation, venting can be costly.
- Amazon Customer Ratings and Reviews: 4.5/5 stars from 200+ reviews. Users praise its performance, with one saying, “Powers our entire house effortlessly.” Some mention high installation costs.
- Why It’s a Good Choice: Combines high flow and efficiency at a competitive price, backed by Takagi’s reliability.
- Ideal Use Case or Who Should Buy It: Large homes (4+ bathrooms) with natural gas, seeking high performance and durability.
6. Noritz NRC66DVNG Condensing Tankless Water Heater
- Compelling Product Description: The Noritz NRC66DVNG is a compact gas tankless water heater delivering 6.6 GPM, perfect for small to medium homes. Its condensing design achieves a 0.91 UEF, offering significant energy savings. With a durable stainless steel heat exchanger and built-in safety features, it’s a reliable choice for cost-conscious buyers who want efficiency without complexity. Its small footprint makes it ideal for apartments or tight spaces.
- Price: $1,322.75
- Key Features and Benefits:
- 140,000 BTU with condensing technology for efficiency.
- Stainless steel heat exchanger for corrosion resistance.
- Direct ignition system for reliable startups.
- 12-year heat exchanger warranty, 5-year parts.
- Benefits: Saves 30-40% on gas bills, easy to install in small spaces (24” x 18”).
- Pros and Cons:
- Pros: Affordable for gas models, compact, reliable in small homes.
- Cons: Lower flow rate limits use in larger homes, venting required.
- Amazon Customer Ratings and Reviews: 4.4/5 stars from 250+ reviews. Customers love its size and efficiency, with one noting, “Perfect for our condo!” Some report issues with hard water scaling.
- Why It’s a Good Choice: Offers a balance of affordability, efficiency, and compact design for smaller households.
- Ideal Use Case or Who Should Buy It: Apartments or small homes (1-2 bathrooms) with natural gas, prioritizing space and cost savings.
7. Rheem RETEX-36 Electric Tankless Water Heater
- Compelling Product Description: The Rheem RETEX-36 is a robust electric tankless water heater delivering 7.5 GPM, ideal for medium-sized homes. Its 99% efficiency rating and self-modulating technology ensure minimal energy waste, while a digital display offers precise control. With no venting required and a sleek design, it’s a practical choice for homeowners seeking reliable hot water without gas lines.
- Price: $829.95
- Key Features and Benefits:
- 36 kW power with self-modulating technology.
- Digital temperature control (80-140°F) with LED display.
- Durable copper immersion heating elements.
- 5-year limited warranty, 1-year parts.
- Benefits: Handles 2-3 simultaneous fixtures, easy to install, quiet operation.
- Pros and Cons:
- Pros: High efficiency, user-friendly controls, compact (14” x 18”).
- Cons: Requires 200A electrical service, not ideal for very cold climates.
- Amazon Customer Ratings and Reviews: 3.9/5 stars from 400+ reviews. Users appreciate the performance, with one saying, “Great for our family of four.” Some note electrical upgrade costs.
- Why It’s a Good Choice: Reliable and efficient, it’s a strong electric option for medium homes at a reasonable price.
- Ideal Use Case or Who Should Buy It: Medium homes (2-3 bathrooms) without gas access, in moderate climates.
8. EcoSmart ECO 27 Electric Tankless Water Heater
- Compelling Product Description: The EcoSmart ECO 27 is a cost-effective electric tankless water heater delivering 6 GPM, perfect for small to medium homes looking to save on energy bills. With a 99% efficiency rating and self-modulating technology, it adjusts power usage to match demand, reducing waste. Its compact design and easy installation make it a favorite for budget-conscious buyers seeking reliable performance without the complexity of gas models.
- Price: $532.47
- Key Features and Benefits:
- 27 kW power with self-modulating technology for efficiency.
- Digital temperature control (80-140°F) for precise adjustments.
- Stainless steel and copper components for durability.
- Lifetime warranty for residential use, 5-year limited warranty.
- Benefits: Saves up to 50% on energy costs, fits in tight spaces (17” x 17”), no venting required.
- Pros and Cons:
- Pros: Affordable, high efficiency, easy to install, great warranty.
- Cons: Limited flow for larger homes, requires 200A electrical service.
- Amazon Customer Ratings and Reviews: 4.3/5 stars from 700+ reviews. Customers praise its value, with one noting, “Perfect for our two-bedroom home, saved us hundreds!” Some mention reduced performance in very cold climates.
- Why It’s a Good Choice: Offers excellent efficiency and a lifetime warranty at a low price, ideal for budget buyers.
- Ideal Use Case or Who Should Buy It: Small to medium homes (1-2 bathrooms) without gas lines, in warmer climates (groundwater >60°F).
9. Stiebel Eltron Tempra 24 Plus Electric Tankless Water Heater
- Compelling Product Description: The Stiebel Eltron Tempra 24 Plus is a compact, high-efficiency electric tankless water heater delivering 5 GPM, tailored for smaller homes or apartments. Its Advanced Flow Control ensures steady temperatures, even with fluctuating water use, while a 99% efficiency rating minimizes energy costs. With German engineering and a sleek design, it’s a reliable, quiet option for those prioritizing quality and ease of installation.
- Price: $529.49
- Key Features and Benefits:
- 24 kW power with self-modulating technology.
- Digital thermostat with precise temperature control (80-140°F).
- Advanced Flow Control for consistent performance.
- 7-year warranty against leaks, 3-year on parts.
- Benefits: No venting needed, silent operation, compact (14.5” x 16.5”).
- Pros and Cons:
- Pros: High efficiency, easy to install, ideal for small spaces.
- Cons: Lower flow rate, requires 150-200A electrical service.
- Amazon Customer Ratings and Reviews: 4.4/5 stars from 450+ reviews. Users love its reliability, with one saying, “Perfect for our apartment, no more cold showers!” Some note electrical upgrade costs.
- Why It’s a Good Choice: Combines German precision with efficiency, ideal for smaller households seeking quality.
- Ideal Use Case or Who Should Buy It: Apartments or small homes (1-2 bathrooms) without gas, in moderate to warm climates.
10. EcoSmart ECO 18 Electric Tankless Water Heater
- Compelling Product Description: The EcoSmart ECO 18 is an entry-level electric tankless water heater delivering 4 GPM, designed for small households or single-point applications like a guest suite. Its 99% efficiency and self-modulating technology keep energy costs low, while its ultra-compact design fits almost anywhere. Affordable and reliable, it’s a great starter option for those new to tankless systems.
- Price: $207.76
- Key Features and Benefits:
- 18 kW power with self-modulating technology.
- Digital temperature control (80-140°F) for ease of use.
- Copper and stainless steel components for durability.
- Lifetime warranty for residential use, 5-year limited warranty.
- Benefits: Saves up to 60% on water heating costs, ultra-compact (14” x 14”).
- Pros and Cons:
- Pros: Very affordable, high efficiency, easy to install.
- Cons: Low flow rate, not suited for multiple fixtures or cold climates.
- Amazon Customer Ratings and Reviews: 4.2/5 stars from 800+ reviews. Customers appreciate the price, with one stating, “Great for our cabin’s bathroom!” Some note limited capacity for larger needs.
- Why It’s a Good Choice: The most budget-friendly option with solid efficiency and a lifetime warranty.
- Ideal Use Case or Who Should Buy It: Small homes, apartments, or single-point use (1 bathroom) in warm climates.
Buying Guide: How to Choose the Best Tankless Water Heater for Your Needs
- Sizing and Flow Rate: Calculate your home’s demand by adding the GPM of fixtures used simultaneously (e.g., shower: 2-2.5 GPM, sink: 1 GPM). For 3 bathrooms, aim for 7-9 GPM; for 1-2 bathrooms, 4-6 GPM suffices.
- Gas vs. Electric: Gas models (e.g., Rinnai, Takagi) offer higher flow rates for larger homes but require venting and gas lines. Electric models (e.g., EcoSmart, Stiebel Eltron) are easier to install and ideal for homes without gas but need significant electrical capacity.
- Energy Efficiency and Costs: Look for a UEF above 0.90 for maximum savings. Gas models save 30-50% on fuel; electric models save up to 60% in warm climates. Installation costs range from $500-$2,000; check for ENERGY STAR rebates.
- Installation Considerations: Gas units need proper venting (PVC or stainless steel) and professional installation. Electric units require 150-300A service upgrades. Confirm compatibility with your home’s infrastructure.
- Maintenance and Warranty: Annual descaling prevents buildup, especially in hard water areas. Choose models with 10+ year heat exchanger warranties for longevity.
- Other Factors: Consider smart features (e.g., Wi-Fi control), noise levels (electric models are quieter), and hard water compatibility (models with stainless steel exchangers perform better).
Frequently Asked Questions (FAQs)
- What is a tankless water heater and how does it work? Tankless heaters heat water on demand using gas burners or electric elements, eliminating standby energy losses of tank models.
- Are tankless water heaters worth the investment? Yes, they save 30-60% on energy bills and last 15-20 years, offsetting higher upfront costs.
- How much do tankless water heaters cost to install and operate? Installation costs $500-$2,000; operating costs are lower than tanks, with savings of $100-$300 annually.
- Can I install a tankless water heater myself? Professional installation is recommended, especially for gas models, due to venting and electrical requirements.
- What’s the difference between condensing and non-condensing models? Condensing models (e.g., Rinnai RX199iN) use exhaust heat for higher efficiency (UEF >0.90), while non-condensing are less efficient but cheaper.
- How do I size a tankless water heater for my home? Add the GPM of simultaneous fixtures and match to the heater’s capacity, factoring in groundwater temperature (colder climates need higher GPM).
Conclusion
Choosing among the best 10 tankless water heaters can transform your home’s hot water experience, eliminating cold showers and slashing energy bills. Our top picks, rigorously vetted using Amazon data and expert insights, cater to every need—from the high-powered Rinnai RX199iN for large families to the budget-friendly EcoSmart ECO 18 for small homes. Use our comparison table and buying guide to match your home’s size, fuel type, and budget. We recommend starting with the Rinnai RX199iN for its unmatched performance. Click the Amazon links to purchase your ideal tankless water heater and enjoy endless hot water today!