Tankless Water Heater Reviews

We spent dozens of hours researching the best tankless water heaters on the market. Like all of our guides, we hope the tankless water heater reviews below will save you time, a few headaches, and money on your utility bill. So without further ado, let’s get started.

The best tankless water heater

We looked at every tankless water heater on the market and our favorite is the Rheem Performance 27 kw (5.6 GPM). 

Here are the top reasons why we think it’s the best tankless water heater:

• Corrosion-resistant parts — One of the most common reasons that tankless water heaters break is because “hard water” leads to corrosion. No manufacturer warranties cover that, so it’s important to buy a water heater built with corrosion-resistant parts. And Rheem builds some of the best.
• High GPMs — The Rheem Performance tankless water heater is very energy efficient which means that even at low inlet temperatures you’ll get a lot of GPMs for a $500 water heater.
• Good value — While Rheem’s tankless water heater isn’t as cheap as EcoSmart’s models, they are still cheap relative to other brands like Stiebel making it one of the best value options out there.

Rheem vs. EcoSmart tankless water heaters

Compared to the EcoSmart 27 kw, one of the top selling tankless water heaters on the market, it is a bit more expensive ($30 more). But in digging deeper we found a lot of customer complaints for the EcoSmart 27kw and started looking more into the product quality, warranty and customer service experience.

Rheem’s corrosion resistant components last longer
All of Rheem’s tankless water heaters are built with corrosion resistant metal, which means that they are less likely to leak due to “hard water.” 

What is hard water you ask? Well in America most water supplies have minerals that can build up in a hot water heater and ultimately corrode the tank. 

EcoSmart’s tankless water heaters by contrast are made of copper, which means they can corrode quickly. And while they claim to have a lifetime warranty, it’s important to read the fine print. 

Here’s what EcoSmart’s warranty says: “SUCH WARRANTIES DO NOT COVER: Product failure caused by liming, sediment buildup, chemical corrosion, chlorine/chloride corrosion, or freezing.”

If your EcoSmart does corrode then customer service will tell you that you should have soaked the heating components in vinegar every six months (which is quite the inconvenience). 

And that’s why the internet is full of bad reviews on EcoSmart’s products like this: “I wish I had never bought this product. I’ve had to replace the heater elements twice in about 3 years at cost of about $250 for the parts ($85 for 2 elements) plus labor for each incident. I have sunk about a $1,000 into this unit and more failures are to come.”

Rheem’s tankless water heaters aren’t perfect. But they receive consistently higher ratings than EcoSmart tankless water heaters. And that’s largely due to their build quality. 

Rheem vs. Stiebel

The company that claims to offer the highest quality product is Stiebel, a German-based manufacturer. 

We compared the Rheem Performance 27 kw to the Stiebel Eltron Tempra 24 Plus. 

At $620 the Stiebel tankless water heater is $115 more than the Rheem and $145 more than the EcoSmart. 

Like the Rheem, the Stiebel Eltron Tempra is built with corrosion resistant materials. So it’s a better option than the EcoSmart. 

But at a price premium of $115 we don’t think it’s worth it given that the quality is similar to the Rheem. 

If you want to see all of the tankless water heaters we reviewed and their prices, check out the table below.

Tankless water heater prices

Want to learn more about water heaters?

We spent hundreds of hours researching hot water heaters and writing the most comprehensive guides on the internet. You can check them out by visiting one of the links below: 

• Hot water heater buyer’s guide — A general overview of what to consider when you buy a hot water heater.
• Tankless water heater buyer’s guide — Pros, cons, costs, and much more on tankless water heaters.
• Heat pump water heater buyer’s guide — Pros, cons, costs, and much more on the most energy efficient type of water heater.
• Gas and electric water heater buyer’s guide — Pros, cons, costs, and much more on conventional gas and electric water heaters.