What tankless water heater is the best? Part of the answer depends on your needs – gas or electric, basic or full of features and whether you’re willing to pay more for superior quality and durability.
In this guide to the best tankless water heaters, we list top models in several categories. The information about each will help you make a buying decision you’ll be satisfied with now and in the years to come.
- Best of the Best Tankless Water Heaters
- Best Selling Tankless Water Heaters
- Best Value Priced Tankless Water Heaters
- Choosing a Tankless Water Heater
Best of the Best Tankless Water Heaters
Here are the best gas tankless water heater and the best electric tankless water heater you can buy.
Overall Best Gas Water Heater: Takagi T-H3S
This is a large water heater suitable for homes in cool climates with 2 bathrooms and homes in warmer climates with 3 bathrooms. The T-H3S is also suitable for small commercial applications, radiant floor heating and filling hot water storage tanks. It complies with Ultra Low-NOx requirements and includes a remote controller. The unit is a condensing water heater with stainless steel secondary heat exchanger.
Its key specifications are:
- Models: Indoor and outdoor, natural gas and propane
- Capacity: 180K BTU
- Maximum GPM:0
- Efficiency: Indoor models, .95; outdoor models, .90. Energy Star compliant
Top Pro: This unit works well in 3-4 bedroom homes and for homeowners committed to reducing energy use and toxic emissions for greener living.
Top Con: This tankless water heater does not offer WiFi connectivity.
Overall Best Electric Water Heater: Titan SCR4 N-210
This is a large electric model that can accommodate up to 2 bathrooms at a time, suitable for a small home, apartment or an office suite. It’s also used for specialty purposes such as a dedicated hot tub or jetted tub. The 240V unit requires dual 50amp breakers. The unit is very durable and is made in the United States.
- Capacity: 21kW
- Maximum GPM:0
Top Pro: It’s ideal for large point-of-use applications and for remodels such as finishing a garage or basement or adding a bathroom when connecting to existing hot water lines or a water heater isn’t cost-effective or possible.
Top Con: Like all-electric models, this unit uses a lot of electricity compared with gas units. If you’re not sure whether a gas or electric tankless water heater is best for your needs, see the section of our Tankless Buying Guide that discusses gas vs. electric with pros and cons.
Best Selling Tankless Water Heaters
These units combine quality and performance that is better than average with a size/capacity suited to most applications. That’s what makes them best selling tankless models.
Best Selling Gas Tankless Water Heater: Rinnai RL94
This is a large, non-condensing water heater suitable for 2 bathrooms in cool climates and 3+ in warmer regions. The Rinnai RL94 is also popular for small shops, office suites and similar commercial settings. It offers a good balance of cost and efficiency. Average operating cost when burning natural gas is about $200 per year. The Rinnai RL94 specifications include:
Models: Indoor and outdoor, natural gas and propane
- Capacity: 199K BTU
- Maximum GPM:8
- Efficiency: .82
Top Pro: This unit makes a large volume of hot water, so it’s a good fit for busy households where a clothes washer or dishwasher runs while one or two showers are also in use.
Top Con: It’s not as efficient as condensing water heaters. Of course, condensing water heaters have their pros and cons too. More information can be found in the section of our Tankless Water Heater Buying Guide about the topic.
Best Selling Electric Tankless Water Heater: Rheem RTEX-13
This unit is also known as the Rheem RTE 13 and Rheem RTEX 13. While its best used at a single point, it does produce enough hot water to serve two locations simultaneously when inlet water is moderate or warm, especially if low-flow faucets are used. The Rheem RTE13 is backed by a 5-year parts warranty.
- Capacity: 13kW
- Maximum GPM:2
Top Pro: There are tens of thousands of these units in service, and they have a proven track record of longevity and reliability.
Top Con: If winters are very cold where you live, this unit will produce less than 2.0 GPM, suitable for just one outlet.
Best Value Priced Tankless Water Heaters
Low cost is only one half of the equation when it comes to value. The units must also demonstrate reliability and durability that is above average. These two models are the best value tankless units on the market.
Best Value Gas Tankless Water Heater: Rinnai High Efficiency/HE V Series
The Rinnai HE V Series water heaters are available in two capacities. They are non-condensing models designed for indoor installation. Rinnai V Series tankless water heaters have 12-year heat exchanger, 5-year parts and 1-year labor warranties. The lack of “extras” keeps their price under $1,000, impressive for quality gas units that deliver this much hot water.
Here are the Rinnai HE V Series specifications:
- Models: Indoor natural gas
- Capacity: 100K and 160K BTU sizes
- Maximum GPM:5 and 9.8
- Efficiency: .81
Top Pro: This is a fantastic choice if you want an affordable, no-frills water heater you can trust.
Top Con: There’s no WiFi option and they’re not capable of water recirculation. Also, if you live in a cold climate, opt for the 160K unit if it will serve more than 2 showers.
Best Value Electric Tankless Water Heater: EcoSmart ECO 18
The Eco 18 tankless water heater is built with copper and stainless internal components for excellent durability and resistance to corrosion. It’s a 240V unit with dual 40amp requirements. The EcoSmart ECO 18 is suitable for apartments, small offices or single points of use where hot water demand is moderate to high.
- Capacity: 18kW
- Maximum GPM:4
Top Pro: It’s backed by an impressive lifetime warranty for residential use.
Top Con: Apart from electric models being costlier to operate than gas, there’s little to dislike about this water heater.
Choosing a Tankless Water Heater
If you’re just beginning your research into tankless water heaters, our comprehensive Tankless Buying Guide is loaded with useful information about gas vs. electric, choosing the right size water heater, the effect climate plays in Gallons per Minute flowrates and general pros and cons for tankless units.
We’ve also prepared buying guides for all the top brands. They offer a wealth of research including all the models, their specifications and current prices for these brands:
- Navien Reviews
- Rinnai Reviews
- Rheem Reviews
- Noritz Reviews
- Takagi Reviews
- Ecosmart Reviews
- Titan Reviews
- Bosch Reviews