6 Best Tankless Water Heaters

Hot Water Output: This hot water heater can deliver anywhere from 2.6 GPM to 5 GPM, depending on how cold the climate and how hot you want your water. With its 24 kW heating system, it delivers a surprisingly steady stream of water. It can handle up to 150 psi, but the water pressure will be minimally affected by the heating process.

With heating temperatures between 80 and 140 F, it will deliver all the hot water you need for your sinks, dishwashers, and showers!

(Note: The output is insufficient for high-flow fixtures, but perfect for low-flow faucets and showerheads.)

Reliability: This is one of the most reliable tankless hot water heaters, though it requires heavy-duty electronic components. It runs off two 60-amp circuits, and may require an electrician or plumber to install it properly. Once it’s installed, however, you’ll find it can handle a lot of regular use—it’s even built to be resistant to earthquake damage!

It’s also one of the most energy-efficient water heaters on our list, with a 240-volt, 1,440 watt operation. If you have limited space, this compact water heater—21.5 x 19.5 x 8.8 inches—is exactly what you need.

Features: The heater comes with built-in auto-modulation controls, which will regulate the hot water output automatically. The Advanced Temperature Controls will keep water temperature consistent as you shower, and you’ll find the digital heating display makes it easy to set and adjust the temperature to save energy or increase the heat of the water. It runs totally silently, and there is no need for venting!

Price: At $700, this is getting toward the pricier side of the scale, but absolutely worth it if you want reliability and user-friendly operation. Plus, with the 7-year leakage warranty and 3-year parts warranty, you know it’s a quality appliance!

Hot Water Output: While most reviewers agree that the water heater can produce anywhere between 6 and 8 gallons of hot water per minute, some have insisted that it gets up to 10 GPM. Compared to the 2-5 GPM common with most hot water heaters, this one performs far better than the rest!

Though it’s a gas heater (and thus costlier to run than an electric heater), it’s still very energy-efficient and delivers hot water with minimal heat loss.

Reliability: The hot water heater is highly reliable, with a user-friendly installation and operation that will make it a dream to run in your home. It’s bigger and heavier than some of the other tankless water heaters on our list, but that actually helps to facilitate the higher water output.

The water connections to and from the heater are larger than average, allowing for a higher flow of water into and out of the heater. The heating can be inconsistent, especially in cold climates, but you’ll find it’s more than enough for any 5+ family home.

Features: The digital controls make it easy for you to adjust your heat settings as desired, and there’s even a remote control for maximum convenience. The heater comes with a built-in lighting mechanism, so no need to futz with a pilot light.

The auto shut-off feature will prevent the heater from overheating, and the safety features are all computerized. There are even altitude settings to adjust your heater to higher altitudes and colder climates.

Price: At $1,225, this is the priciest tankless water heater on our list. It delivers reliability and excellent performance, but it’s close to three times as expensive as our top-rated model.

Hot Water Output: This gas-powered water heater is able to deliver as much as 7.5 gallons per minute—an output almost on par with the Takagi heater. However, though it doesn’t quite match the Takagi’s 10 GPM output, it delivers much more reliable and consistent heating.

You get a short delay (30 second) before the hot water hits, but once it’s on, you’ll find it stays consistently hot throughout your shower. The high output means you can run two or three showers and sinks at once without overtaxing the heating system.

Reliability: The heater is designed to be highly reliable, with heating elements that can produce anywhere from 10,000 to 180,000 BTUs. The commercial and residential settings will allow you to adjust the heater according to its location and use. With an 82% thermal efficiency, it’s a highly reliable heater that will help you to conserve energy—both LP and natural gas, according to your preferences.

The heater is surprisingly compact—just 14 x 23 x 9.3 inches—so it can be installed in any home or apartment.

Features: The digital controls allow you to raise or lower the temperature easily, and you can set it anywhere between 98 and 160 F.

The system is a bit tricky to install, so it’s recommended you use a professional electrician or plumber to do the work for you. However, once it’s set up, you’ll have no trouble using it. The built-in safety controls will prevent the heater from overheating, protect it from frost, and even reduce the risk of an electric power surge damaging the heater.

Price: At close to $940, this is on the pricier side of the scale, but definitely worth owning if you have a large family (5+ members) that uses a lot of hot water. Thanks to the consistency of the hot water output, you’ll never have to worry about cold showers again.

Hot Water Output: The hot water heater delivers a stunning 9.5 GPM, almost on par with the highest-output Takagi model. It’s also surprisingly energy efficient, with a 94% thermal efficiency, meaning there is very little heat loss while the appliance is heating up your water. Thanks to the high flow, you have enough hot water for 4 or 5 showers, sinks, and faucets.

Reliability: Unlike some of the other models on our list, this heater doesn’t suffer from consistency problems. Thanks to its high BTUs (199,000), it heats up water very quickly, providing a steady supply of hot water no matter how long you shower.

The operation of the heater itself is also beautifully simple, and the installation won’t require a professional. You can DIY it all, thanks to Rheem’s Low Nox system. Plus, with the remote control, it’s easy to adjust the temperature and settings without having to step foot in your boiler room.

Note: This heater requires a venting system, one that is surprisingly complex. You may want to consult a plumber to ensure it’s done correctly.

Features: The intelligent electronic controls are designed to make it easy for you to “set it and forget it”. All you have to do is set the temperature to your desired heat output, and the digital controls will keep it at that setting until you change it in person or via the remote. The controls also enhance safety, reducing the risk of overheating, leaking, or frost build-up in winter.

Price: At $1,200, this is one of the priciest tankless water heaters on our list. However, given its reliability and high water output, it’s a decent option to consider.

Hot Water Output: The heater can deliver up to 3.1 gallons of hot water per minute, which means it’s enough for two showers or sinks at once. However, prepare for a long heating time—you’ll have to wait at least a minute for the hot water to come out of the showerhead.

Reliability: The heater is battery-operated, so all of the controls will be powered by 2 D-Cell batteries. The heater will only switch onto gas when you need hot water, meaning it will use far less electricity and gas than other models on our list. If your goal is to reduce your carbon footprint and you don’t need a lot of hot water, it’s your best choice.

Sadly, the heat efficiency is fairly low: just 54 to 87%.

Features: The gas and water controls are easy to adjust, and you’ll find it’s one of the most user-friendly heaters once it’s installed. However, installing it can be quite tricky and will require a professional.

Price: Given its incredibly low price tag—around $220, depending on LP or natural gas consumption—it’s a model we had to include on our list. It may not be the most reliable or efficient, but it’s great for saving money on your energy use and the initial appliance purchase.