6 Best 40 & 60 Amp Tankless Water Heater Review & Buying Guide

Looking for the best 40 or 60-amp tankless water heater? Are you searching for an electric tankless water heater that can work with your current 100 or 150 Amps electric service? Or want to avoid the huge expenses related to electric service upgrades? You are in the right place if your answer to any of the above questions is “Yes!”.

A 40 or even 60 Amp tankless water heaters work smoothly with 100-amp service panels without any issue so this can be pretty money-saving for small families.

But the one thing to note here is that these units are less powerful and usually used as a single point-of-use tankless water heater. The hot water production is not enough to supply whole-house demand and you may need to install multiple such units.

Best 40 Amp tankless water heaters

1. Ecotouch ECO90

• Power: 9kW, 240 volt
• Max flow: 1.8 GPM @ 33°F temperature rise
• Breaker req: 40Amp double pole

The first on our list of low-impact tankless water heaters is the Ecotouch ECO90. Being a 9kW electric tankless unit, the ECO90 can produce hot water at upto 1.8 GPM rate at the 33°F temperature rise. You can use it for the shower if you live in the warm South climate of Florida. This tankless model is popularly used for dishwashers, washing machines, and kitchen sinks. 

ECO90 equips self-modulation technology that provides safety and energy efficiency of upto 99.8%. On average, the electric model costs upto $267 on the annual energy bills. 

The unit also has a digital display and thermostatic control for temperature adjustment in the range of 86°F to 131°F.

2. Ecosmart Eco8

• Power: 8kW, 240volt
• Max flow: 1.66 GPM @ 33°F rise
• Breaker req: 40Amp double pole

Ecosmart is a popular and one of the most trusted brands in the electric tankless water heater market. A subsidiary of Rheem, the Eco8 can deliver hot water at upto 1.66 GPM rate when the temperature rise is 33° F – meaning you can use it for the shower. In colder climates, this model can be used for kitchen and bathroom sinks. It’s also perfect for use in office and business locations. 

This tankless water heater implements a sophisticated self-modulation algorithm that controls the energy used and heat produced according to water flow. It provides both safety and efficiency. The water heater is at least 50% more energy-saving compared to the tank model. 

Eco8 boasts an 8kW heating element with Max 40 Ampere usage. So you won’t need to upgrade your 100 amp service panel to install this model. 

Best 60 Amp tankless water heaters

3. Steibel Eltron DHX 15-2 Plus

• Power: 14.4kW, 240volt
• Max flow: 2.5 GPM @ 37°F rise
• Breaker req: 60Amp double pole

If you are looking for a more powerful electric tankless water heater that can work with your service panel without an upgrade, then a 60 Amp model is perfect for you. One such decent model is from Steibel Eltron. 

The DHX 15-2 plus series model equips 14.4 kW of power and requires less than 60 Amperes of supply to operate. The tankless unit can shell out upto 2.5 GPM hot water at a 37°F temperature rise, which is sufficient to run a shower and a kitchen sink simultaneously in warm climates. You can also use it for showering in cold regions. 

One of the exclusive features of this model is its temperature adjustment feature. Unlike other models, when the water heater’s heating capacity is exceeded, the appliance reduces water flow to maintain a constant temperature instead of lowering it. 

Steibel Eltron DHX plus is CSA certified and comes with upto 7 years of warranty. 

4. Rheem RTEX-13 PLUS

• Power: 13kW, 240volt
• Max flow: 3 GPM @ 30°F rise
• Breaker req: 60Amp double pole

Rheem RTEX-13 is one of the best-rated 60Amp 220v tankless water heaters on the market. The 13kW modern water heater equips a dual copper chamber that delivers upto 3 GPM of hot water at 30°F temperatures rise. That means you can use two showers or one shower and two sinks concurrently in the southern US. In colder northern parts, the unit can output as much as 1.5 GPM of hot water flow. 

RTEX-13 has a sturdy build made out of durable material that stands the test of hard water. It has the popular self-modulation spec that smartly heats water with minimal energy use. The heater features a digital temperature display and a convenient temperature control knob. It is at least 99.8% energy efficient and can drastically reduce the cost of water heating. 

5. Eemax EEM24013 

• Power: 13kW, 240volt
• Max flow: 2.7 GPM @ 33°F
• Breaker req: 60Amp double pole

Eemax EEM24013 is another fantastic option in the 13 kW segment that outperforms the competitor and delivers consistent, unlimited hot water. The electric tankless water heater can shell out upto 2.7 GPM of hot water at 33°F rise, which is sufficient for a low-flow shower and a sink at the same time. 

Speaking of the construction, the tankless model features a dual copper heat exchanger with a brass top that provides durability and a longer lifespan. 

Eemax uses 60 amperes of maximum electric supply and is very efficient thanks to the implementation of advanced self-modulation that prevents energy wastage. If we go by the EnergyGuide estimates, the EEM24013 can cost upto $314 on annual water heating.

It’s also rather easy to install for DIYers. Eemax comes with 5 years of warranty on leakage and 1 year on parts. 

6. Ecosmart Eco11

• Power: 13kW, 240volt
• Max flow: 2.7 GPM@ 33°F
• Breaker req: 60Amp double pole

The last on our list but not the least is the Eco11 from Ecosmart. This 13 kW electric tankless water heater is another reliable option that you can consider. Speaking of the price point, this model is the cheapest among all 13kW heaters on this list. 

Eco11 can render upto 2.7 GPM hot water in warm climates where only a 33°F rise is needed. That means you can run one shower and two low-flow sinks together and one shower in colder climates. It’s perfect for a small family of 2-3 people. The thermostatic temperature control can be adjusted in the range of 80 to 140°F.

With that said, this tankless water heater is energy-star-rated and can provide upto 99% energy efficiency. Ecosmart eco11 comes with a lifetime warranty on electronics and heat exchangers. 

What’s next? Find out the best 110/120 volts 15-amp tankless water heater for your garage.

The buying guide

In this brief tankless water heater buying guide, we are going to talk about only the most important aspects that you need to know while shopping for a tankless water heater. 

Required flow rate

A tankless water heater can provide continuous hot water for an unlimited time, but there’s a limit to how much hot water it can deliver per minute. It’s measured in gallons per minute or GPM. 

If this limit is crossed then depending upon the water heater, either temperature or water flow drops. So you need to properly decide what flow rate you need to avoid the aforementioned problem. It’s also called a sizing tankless water heater. 

Think about how many fixtures you can use simultaneously. A Shower and sink? Or washer and sink? It’s upto you. 

Say, for example, your family uses a shower and a sink at the same time then, add up the flow rate of both to get the required flow rate. 

Eg. Shower + sink = 1.5 GPM+0.5 GPM = 2 GPM

If you need a tankless water heater for a single fixture, then the flow of the fixture is the required flow rate that you need to find in your tankless water heater. 

Temperature rise

It is the difference between your cold water temperature and your desired hot water temperature. It’s an important parameter as the temperature rise, and flow rate are interdependent. 

When the temperature rise is high, the flow rate decreases, and when the required rise is low, the flow rate increases. 

Say, your cold water is 72°F which is the average temperature in Florida, and you want hot water to be 105°F (a common for showers) then the temperature rise in this case is, 

105-72= 33°F.

So you have to look for a tankless water heater that can deliver your required flow rate at the temperature rise you need. 

Usually, this information can be found on the sizing map of the manufacturer.

Your call

So that’s a wrap. The electric tankless water heater is one of the best water heating solutions. It’s highly efficient, compact in size, and provides unlimited hot water. It doesn’t need venting either. The best 40 amp and 60 amp tankless water heaters mentioned above are perfect if you currently have no plan to spend huge on an electric service upgrade or have a small family. They can be used for a single fixture in a cold region and multi-point in a warm region. Need a bigger heating unit? Here’s our favorite 12 GPM tankless water heater.