5 Best Takagi Tankless Water Heaters Reviewed



Installing a tankless water heater in your home gives you more space and plenty of hot water without a big tank wasting space, and some of the best models on the market today come from Takagi. This manufacturer makes many products that have a high flow rate and models with Energy Star ratings that use significantly less energy than your old did. You’ll want to look at some of the tankless heaters we ranked the highest as well as our top tankless heater.

Our choice is the T-H3-DV-N Condensing (Check Price on Amazon.com), which is one designed for use inside a home and use with natural gas. The top features two connections for fast installation with the lines you already have. Its front has a digital display and buttons that show you which one to press to access the menu and which ones to use to change the settings.

Built inside this one is a computer with safety features like a shutdown mode that it automatically enters when the supply reaches such a high temperature that it might scald someone. It even alerts you to potential gas leaks to keep your family as safe as possible. This is an ultra-low emissions tankless heater too that is safe to use in all states in the country.


How to Choose the Right Model

Do You Need an Indoor or Outdoor Model?

Takagi is one of the few manufacturers that makes both indoor and outdoor heaters. Indoor models mount inside your home and usually mount on a wall.  These products work better in warmer climates and areas where the groundwater is more heated.

If you live in a colder climate, you may prefer one designed for outdoor use. These tankless heaters have freeze protection that helps heat the water as it leaves the ground and keeps it from freezing once inside. You cannot mount or use these models inside your home.

What is the Maximum Flow Rating?

Always consider the maximum flow rating before buying one of these appliances, especially if you need to use more hot water in a limited amount of time. This is a measurement that tells you the exact amount of hot h20 that you will get every single minute. It usually ranges between six and 10, but some models have a lower or higher flow rating.

This measurement is also essential for homes with two or more bathrooms or any other features/rooms that use water. A higher flow rating lets you know that you can run your dishwasher or fill your sink to wash dishes by hand and then take a bath or shower without running out of hot water. Higher ratings also allow two or more people to shower one after the other.

Do You Use Natural Gas or Propane?

Many people do not realize that natural gas and propane lines are different and that appliances designed for use on one will not work on the other. Not only are the connection sizes different, but using the wrong one can cause significant damage to your home in the form of a gas leak or even an explosion. Takagi uses N and NG to distinguish its natural gas products and LP to describe those that use propane, also called liquid propane.

Are There Any Safety Features?

If you live in an older home or have kids living with you, you’ll want to look for models that come with built-in safety features. One of the top features offers protection from high temperatures. When the supply research the maximum temperature that you set, the unit will shut down or keep the supply from flowing.

Others come with a feature designed to keep you and your family safe from gas leaks. If the unit detects a leak, it will either shut itself off or alert you via the main menu.

How Many Rooms Can it Serve?

Takagi often tells shoppers how many rooms one of its units can serve at the same time. The T-H3-DV-N Condensing, which is our top tankless heater, can produce enough hot h2o for up to four bathrooms, kitchens or other spaces. The total amount depends on the climate outside, which is what determines the temperature of the groundwater.

If you live in a colder region like middle America, that same model can supply hot water to three rooms. This is because the temperature of the groundwater is much colder and the machine will need to do more work to bring it up to the right temperature.


Top-Rated Picks From Takagi on the Market


1. T-H3-DV-N Condensing (Check Price on Amazon.com)

T-H3-DV-N Condensing

The T-H3-DV-N Condensing gets our nod as the top choice for most shoppers because it works inside your home and with the natural gas line and connections that your old system used.

Designed to help you save space and power, it has a compact shape that takes up a smaller amount of space than comparable models do and comes with an Energy Star rating.

This is also an ultra-low emissions tankless heater that produces far fewer fumes than others do, which makes it safe for use in states like Texas as well as California.

It comes with a built-in computer that handles all the safety aspects of the model to keep your family safe from gas leaks as well as scalding water.

With a flow rating of 10 gallons per minute, this model can supply all bathrooms in your home as well as your kitchen with more than enough supply for daily use.


Meets the standards for designation as an ultra-low emissions product
Allows the supply to flow out at a rating of 10 gallons per minute
Has a built-in computer with safety features that operates the heater


May require that you adjust your gas pressure or have the gas company do it before using it
Requires some adjustments when using it to replace a tank model


2. T-K4-OS-NG (Check Price on Amazon.com)


The top option for those looking for a tankless heater they can install outside is this one, which works in cold temperatures and will keep the H2o from freezing inside.

Even if the temperature outside drops below freezing, you’ll still have the water that you need, though any leaks that get inside can prevent the unit from working correctly.

It has a BTU output of 190,000 and a monitoring system that keeps a constant eye on the temperature to ensure it comes out at your maximum selection.

Unlike other tankless heaters that require some venting, this model is one that you can install without using any vents, but you’ll void your warranty if you do not use authorized techs when installing and repairing it.

We also like that this one has a maximum flow rate of eight gallons per minute, which is enough to supply your kitchen and all bathrooms with hot water.


Maximum flow rate of eight gallons per minute supplies to multiple taps
Continually monitors the temperature to keep it in your specific setting
Offers protection against freezing temperatures outside


Requires an authorized repair technician to handle repairs
Cracks in the case may let in water that causes the unit to stop working


3. T-T-KJR2-OS-LP (Check Price on Amazon.com)

T-T-KJr2-OS-LP Outdoor

Another option that works well as an outdoor model is this one, which works with propane and has a maximum BTU output per hour of 140,000, though you can also turn down the output to less than 20,000 per hour.

Its Energy Star efficiency rating is 82%, which tells you that it uses much less energy than your old model did and that you can save some on your bills once you install it.

This model also comes with most of the hardware and supplies that you need for mounting and connecting it to your home’s gas system.

One of the other top features of this tankless heater is that it has a maximum flow rate of 6.6 gallons per minute, which is more than enough to supply a standard tub, shower or sink.

Built-in freeze protection ensures that groundwater never freezes and bursts inside the lines and that it always comes out at a higher temperature.


Has a maximum BTU output of up to 140,000 per hour
Energy Star rated with a high-efficiency factor
Maximum flow rate hits more than six gallons per minute


Tubing can develop tiny leaks with regular use
May not last as long as you would like it to


4. T-K4-IN-LP (Check Price on Amazon.com)

T-K4-IN-LP Indoor

When searching for models that you can safely install inside your home, consider this propane tankless heater, which has a conversion design that you can use for connecting it to different venting options.

With a BTU output of between 11,000 and 19,000, this model runs more efficiently, which is why it has an 82% efficiency rating from Energy Star. It also comes with all the mounting equipment needed and a special panel on top that keeps it secured on the wall.

Looking at the flow rating lets you know whether one product will work better in your home, and we like that this one has a maximum flow rating of eight gallons, which helps you fill a sink or tub faster and allows you to use more hot h2o in less time.

The one issue reported by customers with this product is that it can take a full minute or more for it to come out after turning on the faucet.


Has a higher maximum flow rate than other models do
Produces between 11,000 and 190,000 BTUs
Controls on the temperature and exhaust keep your home safe


Leaking heat exchangers are a common problem reported by customers
Takes a few seconds or more for hot water to come out of the faucet


5. T-K4-IN-NG (Check Price on Amazon.com)

T-K4-IN-NG Indoor

A solid choice for anyone looking for an indoor heater that runs on natural gas is this T-K4-IN-NG tankless heater. Though you can only use it indoors and it does not come with any freeze protection, it does have a conversion option for using it with direct vents to keep the gas out of your home.

A built-in safety feature shuts the unit down at the first sign of a gas leak to your home and family safe too.

You also get protection from the temperature control feature that keeps the temperature from climbing so high that it might scald or burn someone as it comes out of a faucet.

Energy Star gave this one an efficiency rating of 82% because it runs so well and does not use a lot of energy as it runs. A maximum flow rating of eight gallons helps you get more hot water too.


Safety controls keep the exhaust from venting into your home and the temperature from rising too high
Maximum flow rate hits eight gallons per minute
Conversion option lets you connect this model directly to your vents


May allow cold to come out when it runs out of hot water
Requires much more maintenance than you might expect


Top Picks from Takagi

T-H3-DV-N Condensing

Check Price on Amazon.com)

Takagi makes so many different heaters that finding the top one takes some thought as well as some research, which is why we checked out reviews from customers and used their feedback to see the top one.

Our top choice is the T-H3-DV-N Condensing, which has an impressive flow rating of 10 gallons per minute. It heats up the supply quickly and pumps out just as quickly to fill a sink or tub as fast as possible.

This tankless heater comes with a digital display and buttons for accessing and using its settings and features as well as computer safety features that alert you to problems like leaks and monitors the temperature to keep it from reaching scalding levels.

The compact design of the T-H3-DV-N Condensing makes it a smart choice for smaller homes. You’ll get all the h2o that you need without wasting valuable space in a laundry room or other room.