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The Takagi T-Kjr2-In-Ng Tankless Water Heater At A Glance

Takagi T-KJr2-IN-NG Indoor Tankless Water Heater, Natural Gas
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Top Perk > Built To Last
If you desire a budget friendly heating unit that is built with high quality materials to last you a long time, then the Takagi T-KJr2-IN-NG indoor tankless water heater will make a great choice. This gas fired unit is specially adapted for small homes where low flow requirement is usually common. Besides its durability, one other selling point that has endeared this product to customers is its small size. With a dimension of 6.7 x 13.8 x 20.3 inches and a weight of 38 pounds, this unit can fit into any little space in your home. Although it’s mostly used for single point applications, it can still deliver to two bathrooms in warm weather conditions. There’s no doubt you will get the best value from this unit if you have a small home. Believer it or not, it is the best indoor natural gas tankless water heater in the market right now.

Takagi T-KJr2-IN-NG

Cost: $$$

Model Number: Takagi T-KJr-IN-NG

Weight: 38 pounds

Size: 6.7 x 13.8 x 20.3 inches

Water Flow Rate: 6.6 gallon per minute (GPM)

Type of Unit: Indoor

Fuel Type: Natural Gas

Energy factor: 0.82

Warranty: Residential: 10 year heat exchanger and 5 year parts (residential only. 5/3 in commercial applications)



These days, it’s very difficult to find a household that doesn’t have a water heater. Life has become so much easier since the advent of this technology and it’s no surprise they are becoming one of the most important appliance in a home.

There are two major options for setting up a water heating system in your home: water tank heater and the tankless water heater. The former is gradually becoming obsolete while the later, which is the product of a more recent innovation, is now considered as the best solution for providing hot water on demand in homes.

Tankless water heaters are preferred to traditional water tank heaters because they are generally more efficient and reliable. They consume less energy and provide hot water when you need.

So no more skipping your bath on a chilly morning or worrying about your hands getting frost while doing the dishes. With a tankless water heater safely installed in your home, you can be rest assured your hot water needs will be taken care off.

Over the years, the sizes of tankless heaters have become more compact while a lot of great features have also been added for more convenience and utility. If you’re looking for a reliable product that can give you the best value for your money, then you can never miss it with the Takagi T-KJr2-IN-NG Indoor Tankess Water Heater.

As a product from a well-known and respected brand, Takagi, you can expect nothing less than a great performance and efficiency from this unit. It is one of the highy demanded gas powered water heaters in stock and will make a great catch if you need something between the “middle-of-the-road”.

This unit can produce up to 6.6 GPM of hot water per minute which is not common for water heaters in the same category. Of course, the means more value for you.

Interestingly, the Takagi T-KJr2-IN-NG is among the smallest tankless water heaters in the world, so you can expect it to fit in anywhere. It is ideal for small homes, condos and cottages, and can comfortably supply hot water in two baths simultaneous especially in warmer regions.

Besides its durability, one other selling point that has endeared this product to customers is its small size. With a dimension of 6.7 x 13.8 x 20.3 inches and a weight of 38 pounds, this unit can fit into any little space in your home.

Don’t be deceived by its small size; this is a very powerful system for supplying constant hot water on demand in small homes. It is proven and tested, and has received a lot of positive reviews from customers for its durability and small size.

We believe the Takagi T-KJr2-IN-NG is the most valuable gas powered heating units for small applications on the counter, which is why we have it listed in our choice of the best tankless heaters available in the market today.


When it comes to performance and technology, there are very few brands that can rival the Takagi T-KJr2-IN-NG indoor tankless heater. Most of the capability you can get from a 40-gallon tanked water heater, you can also get with this small unit. This is is even more exciting when you discover that the Takagi T-KJr2-IN-NG is the smallest model in all of Takagi brands.

In terms of technology, this water heater is in its own class. You can expect regular provision of hot water to your entire household anytime and anyhow you want it.

One of the problems with many indoor tankless heaters has to do with uniform temperature distribution. You can set the incoming water temperature at one point, but by the time it reaches the desired location where it is to be used, the temperature may drastically reduce, especially if the location is far from the heating unit. Fortunately, with the Takagi T-KJr2-IN-NG you can easily overcome this limitation.

This is because the machine comes with thermistors (inlet and outlet) and an air-fuel ratio (AFR) sensor that ensures consistent temperature. So you never have to bother about temperature fluctuation. And besides temperature regulation, these features helps to maintain the system’s efficiency and also lessen the release of harmful emissions.

The Takagi T-KJr2-IN-NG is also equipped with temperature controls that automatically turns off wheneven the unit overheats. This is a safety feature which doesn’t come with some other products in the same category.

DIP switches are also included to adjust performance for altitude with various settings.

Additionally, this product will last you for a long time. It is not like one of those units that works for only a few years and becomes useless.


One of the greatest perks about the Takagi T-KJr2-IN-NG is that it doesn’t require electric power. The machine works solely on natural gas with an input anywhere between 19.5k to 140k BTU per hour. This way you can save a lot from energy bills.

The maximum flow rate for this unit is 6.6 gallon of water per minute. But this can be reduced depending on your specific needs. Generally, the Takagi T-KJr2-IN-NG is designed to be used for small houses, apartments or condos  with one or two bathrooms, usually in warmer climates where the incoming water has a temperature approximately 70F. It will work well in colder climates where the temperature of the incoming feed water is around 50F for single baths.

It may interest you to know that you can use this machine along with an radiant floor application or hydronic baseboard for greater utility and efficiency.

As a top grade heater, the Takagi T-KJr2-IN-NG comes with temperature which allows you to adjust temperature of the hot water from anywhere between 99F to 167F depending on your preferred choice. A remote controller is provided to hep you conveniently do this.

The actual rated efficiency for this machine is 82% (or 0.82 energy factor). In order words, the Takagi T-KJr2-IN-NG will help you save a lot of energy…no more skyrocking of your bills.


The Takagi T-KJr2-IN-NG comes with a detailed step-by-step instruction manual that makes installation manual less of a hassle. So with some guts and an undivided attention to detail, you should be able to handle the task on your own and save some money in the process.

While this sounds nice, it might not be the best route. Due to safety concerns, it’s usually better to hire someone who’s a professional to get the job done. Don’t put yourself or your home at risk just because you want to save some ucks.

Since this unit is powered by gas, it will require an outdoor venting to install. The venting can either be done vertically or horizontally. You will need a licensed professional to accomplish this.

Another reason, you should hire a professional is to prevent the warranty that comes with the machine from becoming void. Without installation done be a certified professional, the Takagi warranty won’t be valid.

The product warranty is 10 years on the heat exchanger and 5 years on parts.

The Takagi T-KJr2-IN-NG has an activation rate of 0.5GPM and will need 110V of electric supply to be set in motion. The power cord is included to make electrical installation easier.

When properly installed, this unit will last you a long time and demands very little maintenance.

Other Features

  • Freeze protection for cold climates
  • Diagnostic codes for trouble shooting
  • Surge protection to protect the unit during a sudden electrical spike
  • Small and Compact size with little demand on space
  • Flexible installation Options


  • Long lasting
  • Easy installation and maintenance
  • Comes with advanced switches (DIP) for greater efficiency
  • Great customer service
  • Certified by ENERGY STAR
  • Works well with hard water
  • Great price
  • Relatively high energy factor
  • Very powerful heater
  • Comes with 10 years standard warranty


  • Installation might be expensive
  • Not suitable for large homes
  • Makes more noise

Frequently Asked Questions

Q: Can I share the stack of this unit with the furnace?
A: According to the instructions, you should NOT share this vent stack with any other.
Q: How well does the system handle hard water?
A: If your water hardness is greater than 7, the instructions say that you should install a softener.
Q: Does this include the horizontal vent kit? if not, where can it be ordered from?
A: No it doesn’t. You can order online.
Q: What is the power requirement for this unit?
A: 140,000 BTU
Q: Is this one direct vent?
A: Yes it is a direct vent. Make sure you follow the venting instructions.
Q: Is this concentric vent piping?
A: Yes
Q: Can this product be vented vertically?
A: Yes, this unit can be vented vertical or horizontal using 4″ stainless steel venting.
Q: Does this have a chiller setting?
A: No
Q: What is the maximum GPM for this machine?
A: 6.6 GPM max flow rate
Q: What size gas line is required?
A: 3/4 inch gas line is required.
Q: What's the minimum flow rate?
A: 0.75 GPM flow.
Q: Can I vent this thru a crawl space?
A: Not really. Gravity is needed to evacuate condensation
Q: Can this unit be installed outside?
A: The Takagi T-KJr2-IN-NG is an indoor water heater and as such is meant to go inside the house. If you need an indoor heater, you can pick an outdoor model from the Takagi line-up
Q: I have a two bath house; will this unit be strong enough to carry both bathrooms?
A: The Takagi T-KJr2-IN-NG can drive 2 water outlets without a problem.
Q: Is this a Japanese brand?
A: Yes. They are highly rated as the #1 maker of tankless systems.
Q: Does this have a pressure check valve and back flow preventer included?
A: No it does not.
Q: What are the venting requirements for this indoor unit?
A: 4 inch double walled pipe
Q: Could this unit (or a larger one) be used to reliably run about 600 sq ft of radiant floor plus normal residential use?
A: Please contact the company. They should be able to help out with this.
Q: Can this be converted to propane?
A: No. But a propane model is available.
Q: What is the breakdown specification of water flow?
A: The Takagi TKJr2-IN-NG can provide a 55 degree rise at 5.5 GPM.
Q: The fitting on top of the unit-is it male or female?
A: Stainless female to fit a Schedule 40 4″ Elbow.
Q: Does it come with a temperature controller
A: Yes. A remote control is also included to help you do this conveniently
Q: Can I install it in utility room with furnace in there and venting to chimney duct in basement?
A: Should be ok, the unit itself doesn’t get that hot but the exhaust is very hot.
Q: Can i use galvanized vent?
A: Yes you can use galvanized vent, b-vent or PVC vent.
Q: Can I use an existing old 1/2 inch pipes for gas and water line?
A: No, you need 3/4″

The Bottom Line

The Takagi T-KJr2-IN-NG is a great product that can offer you the best value for your money. Don’t be deceived by its small size; this is a very powerful system for supplying constant hot water on demand in small homes. It is proven and tested, and has received a lot of positive reviews from customers for its durability and small size. However, this unit is not meant to replace large whole house units. If you have a large home, then you may want to consider picking another model in the Takagi line-up. Overall, the Takagi T-KJr2-IN-NG is a fantastic deal at its current price. Don’t hesitate to grab it if you can!


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