Top Tankless Water Heater Reviews for 2025
Estimated Reading Time: ~7 minutes
Top 5 U.S./Based Tankless Water Heater Companies
- Rheem
Rheem has a long-standing history of manufacturing heating, cooling and water heaters. It has an electric tankless unit as well as gas models.
- A O. Smith
A. O. Smith has a strong presence in North America in the field of water heating and boiler technology. They manufacture residential and commercial heating systems, including hybrid and tankless systems.
- Navien
Though originally a Korean firm, Navien is a strong player in the U.S. market for tankless water heaters. Navien is ranked highly in many tankless heater reviews.
- Noritz
Noritz is another brand that appears frequently in roundups of top brands, particularly in the niche of tankless.
- Bradford White
Bradford White is an employee-owned U.S. company that manufactures a variety of water heaters, both traditional and advanced.
The information provided is based on online resources available on the internet.
1. Why Tankless Water Heaters Reviews Matter
In the process of upgrading your home, tankless water heaters are often praised for their efficiency, space-saving, and unlimited hot water capabilities. The spec sheets of manufacturers and their claims are only part of the picture. Tankless water heater reviews based on real hot-water needs and regional conditions are the most valuable.
Your hot water system has a profound impact on your home: it affects your comfort, utility costs, reliability, maintenance burden, and more. If you choose a model that is over-hyped or a bad match, it can lead to temperature fluctuations, insufficient flow or frequent repairs. It’s important to read multiple reviews and understand how they are interpreted before deciding on a water heater upgrade.
This article is a review of what users experience. It includes a critique of the best gas and electric cars, lessons learned from side-by-side comparisons and identifying reliable reviews.
2. What makes a review useful?
Let’s first define what makes a Tankless Water Heater reliable:
- Real-world testing under realistic conditions.
- Use it for a long time, not only the first few weeks.
- Transparency regarding measurement methods
- Reliability, error rates, and maintenance requirements as reported by users of different water heater brands can vary significantly.
- Comparisons with competing models or tank systems
- Independent Sources (consumer websites, homeowner forums) instead of only manufacturer literature
This article will include quotes and references to reviews that meet these standards.
3. Tankless Technology Overview
3.1 What makes them different from storage tank water heater systems
A tankless water heater, also known as an instantaneous system or on-demand water heater, does not store water. A heat exchanger heats the water. This can be a gas burner or an electric coil. The standby energy losses found in a tank-type water heater are avoided.
A tank heater, on the other hand, heats and holds a constant volume of water, so energy is used even when you don’t need hot water. This is often cited as one of the main advantages of tankless models.
Gas vs. Electric: Which Type of Water Heater is Best
Two primary power sources are available:
- Gas tankless water heaters, which are often powered by gas. Tend to have higher flow rates. Those gas water heaters are more common in homes with larger spaces.
- Electric Tankless Water Heater Units are easier to install in certain settings, but have a limited flow rate unless they are heavily wired.
Reviewers typically compare the performance of these two types under load as well as their utility costs and installation complexity.
4. Review of the Top Tankless Water Heater Brands: Gas Models
Check out what users and reviews are saying about some of the top gas models.
4.1 Rinnai High Performance 7.5 GPM – 4.1 litres
Users praise the sleek design and performance of the 7.5 GPM Rinnai High-Efficiency unit on Home Depot’s review site:
“Space-saving, energy-efficient…continuous hot water without running out.”
This unit is often reliable in medium-sized homes. The unit’s ability to control the fan and burner helps it maintain a stable temperature, even when using multiple fixtures.
Some critics mention the cost of installation (venting, upgrading gas pipes) and the fact that the flow decreases in cold climates as the temperature increases.
4.2 Navien & Premium Gas Units
Navien is frequently included in “best of” lists. Navien was mentioned in “9 Best Tankless Unit Brands for 2025” as a top choice among gas tankless water heaters with robust features.
Many buyers mention a stable hot water supply and strong support for the recirculation system. Negative comments include higher part costs and a dependence on high-quality water.
4.3 Other Gas Tankless Water Heater Reviews That Are Worth Reading
2023’s Top 6 Picks” is a good example of a list that aggregates top models. In lists like “Tankless Water Heater Review: 2023’s 6 Top Picks”, gas models by brands such as Rheem, Takagi and Noritz are frequently included.
Positive themes that are typical
- High flow rate / high heating capacity
- Longer life span compared to a tank water heater
- Brand support and solid warranties
Negative themes are often installation complexity, a drop in performance when temperatures rise or sensitivity to water hardness.
5. Top reviews of tankless water heaters: Electric models
Let’s see what the reviewers have to say about electric options.
5.1 Stiebel Eltron / Tempra Series
The Stiebel Eltron Tempra is one of the top electric tankless units recommended in many buyer guides. Reviewers have highlighted:
- Hot water performance with precise modulation and stability
- Compact form factor
- Smaller homes can be more efficient
Many reviews warn that flow can be affected by cold climates and when multiple fixtures are being used at once. Some units require a significant amount of electrical infrastructure (dedicated outlets, high amps).
5.2 EcoSmart Thermomate & Compact Units
EcoSmart 27 is often rated highly in user reviews for electric units. Its compactness and efficiency are praised. EcoSmart is one of the top models in “Tankless Water Heater 2023’s 6 Top Picks”.
Recent tech reviews have praised the Thermomate 4.7 GPM.
It is a great value, it heats the water quickly, and it’s easy to use.
Many electric tankless water heaters emphasise:
- Easy installation (no venting required)
- Quiet operation
- Reduced flow when the temperature increases
- Electrical wiring demands
Electric units are often the most cost-effective and reliable for homes with moderate usage.
What Tankless Electric Water Heater Reviews Emphasise
In reading multiple reviews, recurring evaluation criteria include:
- How well does the claimed GPM hold up under cold inlet temperatures?
- Stability of Water Temperature Under Fluctuations
- Under stress, error codes and shutdowns can occur
- How well does the manufacturer support parts and service?
- What was the complexity of wiring or electrical panel upgrades?
The best reviews are balanced and contain both praise and caveats, rather than making blanket statements.
6. Tankless Water Heater vs Tank Water Heater: Comparative Review Insights
In many comparative analyses, the following patterns are evident:
Features Tankless Reviews Receive PraiseHow do tank water heaters compare?
Hot water continuity Reviewers often mention “endless hot water” when describing the proper loading. If the stored volume is exceeded, tank systems can run out.
Energy efficiency Tankless is praised for reducing standby losses. The tank systems waste energy to maintain heat.
Lifespan and reliability. Many users report 20+ years of good maintenance. Tanks can last up to 15 years.
Installation complexity. Reviews often mention the cost of venting gas lines and wiring. In situ, it is easier to replace tank systems.
Performance under large temperature increases. In cold climates, some reviews of document flow may be affected. The tanks are less sensitive to temperature changes because the water in the tanks starts warmer.
Maintenance demands Reviewers often mention sensor maintenance, descaling and error codes. Tank systems require regular flushing as well as monitoring of sediment.
A vivid quote from an online forum for homeowners sums up the many observations made during reviews:
It was a tank that I replaced with a tankless one. Our propane bill was cut by over half each month when we switched to a tankless system.
Others have also mentioned downsides.
I’ve heard many complaints about tankless water heaters and how they don’t provide continuous hot water.
7. Review Common Complaints
Some criticisms are repeated in dozens of user forums and reviews.
- Flow Drop under Cold Feed — When the inlet water temperature is cold, many units cannot sustain their full GPM.
- Cold Water Sandwich / Fluctuations – Brief bursts before heating resumes.
- Power Dependency – Even gas tankless water heaters fail to provide hot water when there is an electrical failure.
- Frequent maintenance & scale buildup — ignoring annual descaling may lead to performance degradation or error shutdowns.
- High cost and complexity of installation – especially when retrofitting (venting, wire or gas upgrades).
- Unrealistic claims by manufacturers — Some reviews criticise exaggerated flow figures without mentioning temperature or conditions.
- Parts costs or proprietary components — Repairs on some brands are cited as being expensive or slow.
One forum contributor cautioned:
“I think Rinnai’s the most popular brand…cost is higher and maintenance is more frequent.”
Another indicator of the gap in expectations:
Many complaints about tankless water heaters and how they do not provide continuous hot water.
8. How to read and judge hot water heater reviews
Use these principles to make intelligent decisions:
- Check the operating conditions. A unit claiming 9 GPM with a 35°F intake is less useful than a unit delivering 5 GPM with ten intake.
- Check for feedback from long-term users: User reviews that span over a period of a year reveal issues with durability.
- Maintenance and error reports: User complaints about sensor problems or clogs are a red flag.
- Take into account the installation context. A positive review for a unit installed in a new building may not be applicable to retrofits.
- Compare parts, brands and services: A model that has excellent reviews may not be the best if you have limited access to repair services.
- Compare real savings with cost. Many reviews mention fuel savings, but check if they are only theoretical.
- Be on the lookout for marketing or bias. Some reviews may be promotional. Check with independent platforms or user forums.
Important Note:
A glowing spec sheet doesn’t equal reliable performance. The best reviews of tankless water heaters are those that test them under real household conditions over time, mention maintenance issues and consider installation options. Triangulate reviews and don’t take one review as gospel.
10. Conclusion:
It is only by focusing on reviews of tankless water heaters that you can gain the clarity and understanding that specifications alone cannot provide. Gas and electric models are praised for their ability to deliver a steady flow of hot water, resist wear over time, and adapt to real-life household variations. Many reviews have also highlighted common pitfalls, such as overstating capacity, undervaluing the importance of maintenance and ignoring installation complexity.
Review reviews carefully: Read multiple sources, examine test conditions, consider user feedback and match the capacity of your home’s actual water consumption. Next, I’ll build you a list of “best-reviewed models for high performance in your climate”.
