Takagi T-K4-OS-NG

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If your water heater does not have a warranty but requires maintenance over and over again, it is time to change it. You have to get a new one which can stay as a lifelong friend and fulfill all your hot water supply demands. Luckily, we have more choices today. The time of conventional water heater has gone. We have new models today that are more efficient in performance and save you money over time as well. Therefore, we have done the homework for you, so that you can opt for the best water heater with new and advanced standards.

After canvassing all the highs and lows, we are 100% sure to say that Takagi T-K4-OS-NG is one of the best tankless water heaters in the market. From all possible aspects, it is a lot better than conventional models. You do not have to deal with stored water, or the amount of energy you are consuming to relish its benefits. It secures you from all ways while flooding with all the advantages which are immensely tough to find in other water heater models.

In case you are thinking how exactly conventional models are costly in the long run, it is because of energy consumption. They pull significantly more energy since there is a large tank. They need to run for longer in order to heat the entire tank. Even if you require a small amount of water, it will perform the same massive task and waste energy. Apart from this, in most old models, the heat escapes from the tank. For that reason, the water inside stays cool all the time. You have to run your heater continuously to maintain the temperature.

On the other hand, advanced tankless water heaters like Takagi T-K4-OS-NG are a totally different game. It is safe to say that they operate on demand. It only draws energy when you need hot water for a very limited time. That is why they run less frequently and draw less energy. Your energy bills cut in almost half and allow you to save thousands of dollars during its lifespan. Therefore, for most consumers, Takagi T-K4-OS-NG is a smart choice.

Is There Any Hype Factor?

In reality, there isn’t. It is all fact. If you check the statistics, you will see that these units sell a lot. For a company like Takagi, it is tough to keep them in stock. Consumers from all walks of life open their wallets for greater efficiency, and greater savings. The tankless models allow them to go green too with a cool touch. They really warm the hearts and give an entire home a contemporary look. You relish endless showers in all severe seasons.

In addition, there is one thing very simple. When you opt for tankless models, you do not look for how many gallons it holds. In fact, the entire scenario changes in assessing the quality of it. You have to look for different sets of things in order to compliment your needs. For example, power source, size and flow rate, energy efficiency, warranty, and ratings.

Takagi T-K4-OS-NG Tankless Water Heater

The Takagi T-K4-OS-NG Tankless Water Heater released in 2010. The manufacturers of Takagi improved many of the features from the TK-3. They made sure they are handing something more special and useful which is smaller in size (138 inches wide only) as well.

Like all the advanced models, Takagi T-K4-OS-NG is also an ultra-compact design which can be mounted on a wall. However, please bear in mind that because of its built-in power venting system, it is for outdoor installation only. If you are looking for something which can be installed inside the home, this is perhaps not for you. Since the specification and features of this tankless water heater are different.  Furthermore, it does not require additional category 3 venting or vent caps. It means you do not have to struggle with installation either. The installation will be one step easier for you. All you need is to follow the instructions warily.

The overall quality and lifespan of Takagi is extraordinary. Even after a decade, it works flawlessly. You do not need to replace it because of leaks or other small issues, which are quite common among conventional brands. According to its users, Takagi is also the quietest and safest tankless water heater. Even after working for months, it does not make any sound. Moreover, their energy bills have gone down to at least 20% after installation.

Other than that, it is designed for larger houses. If you have a 4-bathroom house, the hot water will never run out. In fact, some consumers have bought two to three units of Takagi T-K4-OS-NG tankless heater. One is for their house, and the second one is for their garage.

Product Features:

  • Dimensions of Takagi tankless water heater are 8.5 X 13.8 X 20.3 inches.
  • It weighs around 43 pounds only.
  • Inlet, outlet thermistors for constant temperature monitoring.
  • It is in white color, without the requirement of any batteries.
  • 8.0 GPM max flow rate.
  • 190,000 BTU.
  • The Takagi Company offers a 5-year warranty on heat exchanger.
  • Besides, there is a 3-year warranty on parts and 1-year warranty on labor too.
  • In order to avail the warranty, your unit should be installed by a licensed technician.
  • There is built-in freeze protection.
  • No venting required.
  • The only con about this product is it isn’t available for international shipping.

Concluding Thoughts

So, if you want precisely the amount of hot water you need, opt for Takagi. It isn’t a new tankless water heater product. Unlike others, it has proven its efficiency. Therefore, when you invest in it, you know that you are buying something which has already satisfied thousands of customers. Other than that, the Takagi Company goes a step further in order to win its customers’ expectations. For example, the entire product is well packed, and the shipping time is great as well if you are placing an order on Amazon. They always deliver on time. All in all, it is a product easier to live with. It is difficult to imagine a life without it.

Tech specs


Pros & Cons


  • One of the biggest advantages of this water heater is that it will save you a lot of money on your energy bills. Indeed, it is possible that you could cut down the bill by as much as twenty percent. This is certainly an improvement on typical 40G units. As well as this, the water heater is surprisingly quiet, guaranteeing it won’t wake you up in the middle of the night. The heater is tankless and considerably compact so you won’t have to worry about it taking up much space in your home. We’re also delighted to be able to tell you that the heater has a long life and could easily keep the water in your home hot for over 10 years. A system like this is ideal if you have anything that uses a lot of water such as a jet tub or even a soaking tub.


  • Easily the biggest disadvantage of this system is that you do need to pay for a professional to set it up. Without a pro team installing your water heater, you will void the warranty which will make things difficult if your heater ever needs a repair. It is also worth being aware that the warranty does not cover bad weather which should be a consideration if you are installing it outside.

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