Best Tankless Water Heaters at Amazon (2026 Reviews)
Top-performing on-demand water heaters available on Amazon for every home and budget
Last Updated: 2026-01-09
Quick Summary
- Amazon carries a broad range of electric and gas tankless units; verify seller info and Amazon return policies before purchase.
- Match GPM to your household demand (1-2 fixtures vs. whole-house use) and check site electrical/gas capacity.
- Electric models are simpler to install but need heavier wiring; gas models deliver higher flow but need venting.
- Pay attention to warranty coverage and Amazon’s extended protection options for peace of mind.
Top 5 Products at Amazon
1. Rinnai RL75iN Indoor Tankless Water Heater (RL75iN)
$900 - $1,400
A high-performance gas tankless unit popular on Amazon for whole-house applications. The RL75iN balances strong flow rates with energy-efficient operation and smart diagnostics.
Key Features
- Up to ~7.5 GPM (model-dependent) for simultaneous showers and appliances
- Modulating gas valve and built-in recirculation compatibility
- Compact wall-mounted design with digital temperature control
- Advanced safety and diagnostic monitoring
✅ Pros
- Reliable brand reputation and consistent hot-water delivery
- Good gas efficiency for lower operating costs
- Robust build suited for whole-house use
❌ Cons
- Requires professional gas and venting installation
- Higher upfront cost than electric alternatives
Best For: Homeowners with mid- to large-size homes wanting a dependable gas whole-house tankless unit
2. EcoSmart ECO 18 Electric Tankless Water Heater (ECO 18)
$250 - $450
A top-selling electric tankless model on Amazon for homeowners who want an affordable, compact solution. The ECO 18 offers on-demand heating for small- to medium-sized homes with proper electrical service.
Key Features
- Digital temperature control in 1°F increments
- Self-modulating technology to save energy
- Compact, wall-mounted design ideal for point-of-use or whole-home (in mild climates)
- Lifetime limited warranty on heating chamber (varies by seller)
✅ Pros
- Excellent price-to-performance ratio on Amazon
- Lower installation complexity if electrical panel can support it
- Energy-efficient operation with good customer reviews
❌ Cons
- Needs significant electrical capacity (multiple 240V breakers)
- Limited flow in cold climates for whole-house use
Best For: Budget-conscious buyers on Amazon looking for an electric tankless for smaller homes or point-of-use applications
3. Rheem RTEX-18 Electric Tankless Water Heater (RTEX-18)
$200 - $450
A reliable electric point-of-use and small whole-home option commonly sold through Amazon third-party sellers. Rheem’s RTEX series is known for straightforward controls and consistent performance.
Key Features
- Tempered copper immersion heating elements
- Digital thermostat with LED display
- Compact design for under-sink or garage installation
- Multiple model options to match household needs
✅ Pros
- Affordable and widely available on Amazon
- Simple to operate and maintain
- Good for retrofits and smaller load applications
❌ Cons
- Requires adequate electrical upgrade for whole-house use
- Not ideal for high simultaneous demand
Best For: DIY-savvy homeowners shopping on Amazon who need an affordable electric unit for point-of-use or small households
4. Stiebel Eltron Tempra 29 Plus (Tempra 29 Plus)
$700 - $1,000
A premium electric tankless heater offered on Amazon with advanced flow control technology. The Tempra 29 Plus delivers steady temperatures under varying flow conditions and is a favorite for colder climates when paired with appropriate wiring.
Key Features
- Advanced Flow Control to maintain temperature during pressure changes
- High-end digital temperature control and diagnostics
- Robust German engineering with quiet operation
- Requires 3-phase or multi-breaker 240V service for peak performance
✅ Pros
- Excellent temperature stability and build quality
- Good for homes needing higher electric hot-water capacity
- Long-term reliability and solid warranty
❌ Cons
- Significant upfront cost and likely electrical upgrades
- Heavier than basic electric models and pricier on Amazon
Best For: Homeowners who prefer electric solutions with premium temperature control and don’t mind higher installation costs
5. Takagi T-H3-DV-N Condensing Tankless Water Heater (T-H3-DV-N)
$1,000 - $1,600
A high-efficiency condensing gas unit available on Amazon for whole-house use, known for strong flow rates and low operating costs. Takagi’s condensing design recovers heat for improved efficiency.
Key Features
- High flow rate up to ~10-11 GPM (model dependent)
- Condensing technology for increased efficiency
- Direct-vent design and outdoor/indoor compatible options
- Compact footprint with digital controls
✅ Pros
- Best-in-class gas efficiency lowers energy bills
- Handles multiple simultaneous fixtures with ease
- Durable construction and good Amazon availability
❌ Cons
- High upfront price and professional installation required
- Requires condensate drainage and compatible venting
Best For: Large households and contractors buying on Amazon who want a top-tier gas condensing tankless heater
Frequently Asked Questions
Can I install a tankless water heater myself after buying on Amazon?
DIY installation is possible for experienced homeowners, especially with electric point-of-use units, but gas tankless heaters require correct venting, gas-line sizing, and code compliance, so professional installation is strongly recommended. If you buy on Amazon, confirm the seller provides all parts and consult the manufacturer manual; improper installation can void warranties.
How do I know what GPM I need for my home?
Estimate simultaneous fixture use (e.g., two showers and a dishwasher) and add typical GPM values (shower 1.5–2.5 GPM, dishwasher 1–2 GPM). Compare that total to the unit’s GPM at your local inlet temperature (winter values on Amazon listings are most conservative). When in doubt, choose a slightly higher-capacity model or consider a hybrid setup with point-of-use units.
Are tankless water heaters sold on Amazon covered by manufacturer warranty?
Yes — most manufacturers honor standard warranties regardless of Amazon as the retailer, but warranty terms vary. Keep purchase records and register the product if required. Check Amazon product pages for explicit warranty notes and verify with the manufacturer before buying.
Do electric tankless heaters save money compared with storage tanks?
Electric tankless units can reduce energy waste by heating on demand and may lower operating costs if your household uses hot water intermittently. Savings depend on local electricity rates and usage patterns; gas tankless units usually offer better long-term savings in larger homes due to higher efficiency and lower fuel costs.
How quickly will I get my tankless heater after ordering from Amazon?
Delivery times vary by seller, model, and shipping options. Many popular models on Amazon offer fast shipping or Prime-eligible delivery; larger or boxed gas condensing units may require freight shipping and longer lead times. Check the Amazon product page for estimated delivery and seller notes.
Final Thoughts
Amazon makes it easy to compare specifications, customer reviews, and prices across electric and gas tankless water heaters. For most homeowners seeking a balance of reliability and performance, the Rinnai RL75iN (editor’s pick) is a strong gas option for whole-house needs. If budget and value matter most, the EcoSmart ECO 18 (best value) offers excellent performance for smaller homes or point-of-use installs when paired with proper electrical service. Before buying on Amazon, size the unit to your peak demand, verify electrical or gas compatibility, and plan for professional installation where needed. Use Amazon’s product Q&A and verified reviews to confirm real-world performance, and keep warranty and installation documentation for future support. With the right model and proper installation, a tankless water heater bought through Amazon can deliver years of reliable, efficient hot water for your home.
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