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Takagi T-H3-DV-N In-Depth Review For 2021

The Takagi T-H3-DV-N can produce 10-gallons per minute, which is a hot water output that’s ideal for large to medium households where several water faucets are used at the same time.
Note: This post may contain affiliate links. This means that at no cost to you, we may receive a small commission for made purchases.

Because it has such a high GPM rate, the Takagi T-H3-DV-N water heater can serve about three to four bathrooms with endless supplies of hot water. Its condensing capabilities help make it a remarkably silent tankless water heater, which is perfect for those like the quiet.

Although, that’s something you’d expect from a high-tech tankless water unit.

The Takagi T-H3-DV-N heater also doesn’t have a high nitrogen oxide emission rate. It’s shallow. It has 199,000 BTU gas inputs, a self-modulating heating mechanism, and high energy conversion features.

This indoor tankless water unit also has a 0.95 energy factor, making it an excellent energy saver water heater. Measuring 11.2×17.8×24.9 inches, it’s also amongst the smallest units in its range, which means it can be installed in tiny spaces.

Technical Features of Takagi T-H3-DV-N

Takagi T-H3-DV-N Features

This tankless water heater has very many exciting features.

If you want to know why it’s so popular today, take a look below at what it has inside.

Revolutionary Water Condensing System

One of the best things about this tankless water heater is its innovative condensing technology. Its condensing technology utilizes two heat exchangers. The secondary heat exchanger has been manufactured using high-quality stainless steel.

This type of steel gives you the ability to enjoy corrosion-free operation in low-temperature and acidic environments. On the other hand, the primary heat exchanger is manufactured using high-quality copper alloy so that you can get reliable and durable water heating.

Such strong materials offer excellent resistance to the mechanical and thermal stress that happens at high temperatures.

The advanced design it has provides users with high energy efficiency.  Its over 0.90 energy factor complies with the low NOx standards, making it somewhat of an eco-friendly, green tankless water heater.

It’s perfect for people that live in areas that have strict emission laws. Condensing water units are some of the most advanced heaters on the market. Yes, they might be more on the expensive side, but you’ll be saving big time on energy.

Improved Safety

Takagi T-H3-DV-N Safety

Proper combustion can maximize the unit’s performance and saving. That is why it’s essential. Furthermore, you’ll be safe from carbon monoxide exposure and sooting when your unit has proper combustion.

That is why most, if not all, Takagi water heaters have an AFR or air-fuel ratio sensor to make sure there’s an appropriate mixture of gas and air. Internal freeze protection makes sure your device won’t get damaged during the winter seasons.

So you won’t have to worry if you’re someone that lives in freezing weather environments.

The Takagi T-H3 water heater also has a flow and bypass adjustment valve, which are features that are only found in the best of the best. The valve provides users with optimal water flow accuracy and control.

It also provides durability, especially during highly demanding situations, like when the water heater is being used commercially.

The other safety features it has included; the hi-limit switch function that protects the surrounding and the heater from extreme weather environments, an overheat cut-off fuse feature that switches off the unit if its heat exchanger gets exposed to excessive heat conditions and other thermistors and sensors that ensures smooth operations.

High Flow Rate

Compared to a standard electric unit, you can expect an output of around 10-gallons of water per minute from the Takagi T-H3. Usually, electric water heaters only deliver about 2-4 gallons per minute.

In simpler terms, this tankless water heater will provide you with enough hot water at any given time.

Natural Gas Support

Whenever there’s cold water in the unit’s lines, you can expect the device’s internal burners and heat exchangers to do what they’re meant to do immediately. In other words, the unit is continuously heating water.

Meaning, you’ll never run out of hot water.

Advanced Electronics

Another good thing about the Takagi indoor tankless water heaters is that they have in-built temperature controller features. The outdoor water heaters manufactured by them have wall-mount remote control functions.

The unit’s advanced diagnostics system, electronics, and LCD screen help make it a lot easier to troubleshoot the device.

The controllers use functions like; an information button to show you water flow, outlet and inlet water temperature in Celsius and Fahrenheit, error display, status indicator, and push buttons, which all help make it incredibly convenient to use.

Specifications of Takagi T-H3-DV-N

Takagi T-H3-DV-N Specifications

The Takagi T-H3’s specifications should help give you a better idea of why this tankless water heater is so wonderful:

Flow Rate

The Takagi T-H3 offers 10-gallons per minute. That is way more than you’ll get from the standard electric water heater unit that gives an output of only around 2-4 gallons per minute.

If you’re looking for something that’ll provide you with hot water any time you want it, this is it.


This unit requires at least about 199,000 BTU an hour to work correctly. So you’ll need to ensure you have ground lines that can accommodate that. In some cases, you might have to install some special parts to enjoy the heater’s full wattage.


It weighs around 60-pounds, which means it’s something you can’t casually carry around.

Installation of Takagi T-H3-DV-N

Takagi T-H3-DV-N Installation

This unit is user-friendly, and installation isn’t too complicated.

There’s a definitive user guide inside the package with step-by-step instructions on how you can install the heater. The unit has a power cable included, integrated control functions, and a Schedule 40 PVC for venting.

Since AO Smith now owns Takagi, it’s advised you buy the valve kits from AO Smith with the 9007604005 Isolation Valve Kit tag. Some areas have water that has high acidic proportions, and if you’re someone that lives in such areas, then you’ll need the 9007607005 Neutralizer Kit.

Since it’s a heater that uses condensing technology, you won’t be required to have exhaust vents made of stainless steel. PVC will do just fine.


High Volume Output

We’ve already mentioned this before, but one of the best things about the Takagi T-H3 water heater is the 10-gallon per minute hot water output.

With this kind of output, alongside a 199,000BTU gas input, this indoor tankless water heater can comfortably serve 3-4 bathrooms, faucets, and washers all at the same time without failing.

If you’re running a small business with many employees or a big household, this is an ideal option that’ll provide everyone with hot water whenever they need it. You don’t have to worry about the taps suddenly running cold with this tankless water heater.

Low Nitrogen Oxide Emission

This indoor tankless water heater unit has ultra-low NO2 emission rates and doesn’t emit any poisonous gases into the home or business premises. That, in turn, makes it an eco-friendly and green device with little to no environmental footprints being left behind.

In addition to this, its high-tech condenser helps make it an incredibly silent unit, an excellent feature for something designed to be indoors.

High Efficiency

This indoor tankless water heater unit has many cost-cutting features that help make its energy efficiency better. It’s got a self-modulating heating feature, a diagnostics system, surge protection, over-heating, and anti-freeze protection, as well as a 0.95 energy factor.

With this water heater, you can save a lot on your energy consumption. Also, the device’s advanced features make sure that the unit serves you for a long time.

Compact Overall Design

With a body that measures 11.2×17.8×24.9 inches, this water heater is relatively compact. Not only does this make installation a lot more flexible, but it also helps save a lot of space.

It’s ideal for those people that don’t have a lot of space to work with. Whether you’ve got a small or big house, you won’t get a headache mounting this heater.


This unit features some of the best American and Japanese water heater technology. These features ensure longevity and durability. It has a 15-year limited warranty if the unit is being used domestically.

If it’s going to be used commercially, then you’ll get a 10-year limited warranty. However, both enjoy a 1-year conditional warranty when it comes to labor and a 5-year limited warranty when it comes to parts.


Expensive Installation

The Takagi T-H3-DV unit has high installation costs. One of the reasons why it’s so expensive to install is because it’s gas-powered. Most households don’t have gas pipes that are compatible with it.

It means that you’ll have to retrofit the water and gas pipes to accommodate the heater. Also, the water heater needs a combustion vent so that the smoke from the burning gas can be evacuated.

But, the PVC venting makes sure that there’s no leakage of the pipes and that venting stays cool all the time.

Temperature Drop

Like most high output indoor tankless water heaters, this unit may be a little slow at providing you with water at first. The water temp might drop by around 1 or 2 degrees for a short time when used heavily.

However, the heater quickly compensates for this loss, and users might not even notice this change.


Wrapping Up

Takagi T-H3-DV-N Conclusion

This indoor tankless water heater certainly has many qualities.

However, it’s undoubtedly amongst the most powerful tankless water heaters on the market. Although Takagi themselves can be a bit modest about how strong this particular unit is, there’s proof that it can comfortably service more than three bathrooms simultaneously without fail.

Many large households have enjoyed this specific feature this unit has. Its compact size also makes it something that can comfortably fit almost anywhere, and it ensures it consumes very little space.

If you’re looking for one of the most effective and efficient ways to heat the water in your home, look no further. The Takagi T-H3-DV indoor water heater is what you need in your life. 

It is one tankless water heater you need to consider getting for your home if you’re someone with a large household and don’t want to run out of hot water. This excellent product from Takagi will ensure you’re always one faucet or tap away from hot water.

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Charlie Hardcastle


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