Takagi T-KJr2-IN-NG Indoor Tankless Water Heater, Natural Gas – Rheem Tankless Water Heater – Amazon.com


A gas-fed model that is suitable for smaller homes. Professional installation, though somewhat costly, is suggested.


  • 140,000 BTU. Voltage: AC 120V
  • 6.6 GPM max flow rate. Water connection location- bottom
  • 4-Inch category III stainless steel venting required
  • Inlet, outlet thermistors for constant temperature monitoring
  • Energy factor of 0.81-0.83


T-KJR2-INNG Features: -Tankless water heater.-Natural Gas.-Can be converted into a direct-vent unit.-Indoor installation only.-BTU/hr: 19,500 140,000.-0.82 Energy factor.-Flow rate: 6.6 GPM maximum.-Cost-efficient and environmental friendly.-Perfect for light residential and radiant heating applications.-Energy star. Dimensions: -Overall dimensions: 20.3″ H x 13.8″ W x 6.7″ D.

The T-KJr2 model is the smallest unit in the Takagi line-up. The T-KJr2 is perfect for light residential (i.e. small apartment units) and radiant heating applications.

299 customer reviews

but like everyone else said that these things are rock solid …

After reading many reviews and research about this product last summer, plus getting local advise from friends who also have tankless water heater systems installed. I looked around at how they are installed and the local laws on how to do it properly. The major downside of buying this product on Amazon and DIY install is that you loose the warranty aspect, but like everyone else said that these things are rock solid and easy to maintain.The first thing when you get this is the fact that its small and light. And when you open it up, you are just stunned of actually how much room is not being used inside the case too! It’s a feat of engineering that you are able to get 6+ gallons per min of perfectly hot water from this unit without end.I was worried about Installing the unit right so I took my time and did my homework. I probably went to Home Depot & Lowes 20 times during this project over the course of 4 days as I had to relocate the unit to make routing the exhaust easier on myself. I built a simple wooden frame next to an open vent in the craw space below the house and attacked the unit to it. Since the exhaust is literally inches away, I just custom built a metal adapter to cover the vent perfectly, slide in a vent duct and attached it to the unit with no issues. I also used high temp, fireplace sealant to make sure no outside water ever got through the event and then used aluminum tape to seal any loose vent cracks.I would highly recommend getting the Webstone Heater Service Valve Kit as it’ll make life easier to service the unit down the road. http://www.amazon.com/Webstone-44443WPR-Isolator-Tankless-Construction/dp/B005Q5LXY6I would also recommend using flexible water and gas lines with valves for all in and out piping to make it easier to install. I would also recommend to use valves between the Heater Service Valves and the unit so you can easily remove the heater if you ever need to. I did not do this, but I may down the road.Other than what I mentioned above, after doing it once, I’m very confident in doing it again and install this in just a few hours now that I have the proper tools and knowledge in knowing what simple things to get that kept getting this project finished earlier.

Great deal, easy to intall. Requires reading, of course. Otherwise not beyone what most home owner already know.

I purchased this water heater from Amazon after 3 attempts to have Sears install a traditional 40 gallon (short). Problems were so numerous but not relevant to this review. Suffice it so say my frustration level reached to the point that I started thinking out of the box. I need hot water, my current one had died and I had already read several item about these type of water heater but really never consider them until I logged on to Amazon, I looked at their offering then went to Consumers Report plus consulted with a local plumber friend who, in the past had installed Rheem tankless water heaters but was not particularly impressed with them. After reading about Takagi (an extremely creative Japanese manufacturer ) at Consumers Report (they rated this water heater as a outstand product but service was only fair). The box warns that the warranty is void if it is not installed by a Takagi Certified Technician. Based on other reviews on Amazon the US based service techs are board-swappers and not really able to repair leaks of other minor problems. Yet they are extremely expensive. So I decide to attack it myself, primarily so that any future repairs necessary could be done by me, since I had installed it. The manuals are excellent and quite detailed. You should read the complete set of manuals, from end to end before attempting assembly. I did so, and decided to try it. Remember though, natural gas can be dangerous so if you feel this is something that you are not comfortable with, do not attempt it. Natural gas appliance improperly installed, can be dangerous, explode and totally destroy your home. I am by trade a computer scientist not a plumber but I do have close access to one should I run into any problem. Just make sure your gas it COMPLETLY TURNED OFF, open any gas valves you can and let gas in the line escape before attempting any type of gas installation. Don’t smoke while working with gas. Also understand that if you install it yourself the warranty is void. But from other comments found on Amazon, it’s worthless anyway. The water heater was very easy to install. I was able to use existing gas lines, water lines and vents so this made the job easer of course. I cut 6 copper pipes and soldered these to the existing water pipes after disconnecting and removing the old water heater that was in a basement area. I then built a wood frame with 2/4″ lumber and put 3/4″ ply wood (not particle board) on the frame. I then mounted the Takagi on this surface with the provided hardware. I then mounted the entire frame to a 2/8″ floor joist using the 2/4″ lumber that extended beyond the frame. I then mounted the 2/4″ to the concrete floor. That was 90% of the work. It took about 1 hour to make the water and gas connection (remember the water and gas are turned off at the main). I soldered the joints and waited until the next day. Then I turned the water main on and found one soldered joint had a drip-drip. I unsoldered that joint trimmed the edge a bit then resoldered the joint. The drip had stopped. I had already connected the gas lines first and used pipe dope on the joints. I then turned the gas on for 15 seconds then off again and started sniffing ever joint. I could not smell any gas so I turned the gas back on and using soapy water and a small paint brush soaped every gas connection while looking closely for any kind of bubbling. I found none, so I left the gas on, connected the thermostat that was included. The thermostat requires a 120V AC outlet. This is to spark the ignition. I set the thermostat to 122 degrees F, then mounted it on the wall. I then went upstairs, turned on the kitchen hot water and in about 5 seconds I had hot water. It has now been installed for almost 2 weeks in a 3 bedroom 2 1/2 bath house and for the first time in years I’ve we can run the dishwasher 3 times a day, wash 3 loads of clothes, and have 4 or 5 people take a very hot shower with endless hot water. How long will it last without failure? I have no idea. If it fails, I’ll post here. But at this prices and ease of installation if it lasts only 2 years it will have paid for itself. No Einstein required.UPDATE: As promised this is a update as of 7/8/2013. The Takagi water heater has now been installed for approximately 2 months and continues to works perfectly with no problems at all so far. I would change on thing in my first review we have found 131 degree F setting to be the best. I might also note that our natural gas bill has dropped approximately 1/3 of its usual rate for this time of year.UPDATE: Today’s date: 7/19/2014 – I have received several questions from individuals about this post, so I decided to update again. I installed the Takagi originally on May 25, 2013. It has been running for almost a year and a half now. I still love the product and have had absolutely no problems with it. I did get my plumber friend to take a look at it and he was impressed. He did mention that most tankless water heaters he had dealt with, specifically required horizontal venting rather than vertical as I had done using my old water heater’s vent pipe, which ran to the roof. So early this summer I re-read the Takagi manual much more closely than before and indeed he was right. Takagi “requires” that the water heater be vented horizontally to a side vent. So I went to Home Depot and bought about 20′ of aluminum vent pipe, a new vent connection kit, duck tape (the Silver metal surface kind) and one vent elbow plus a outside vent cover. Total outlay was about $25. I drilled a hole through the basement wall (cinder block) where it would exit under a redwood deck. I then ran the vent pipe from the water heater vent to the hole in the cinder block wall and connected it to the cover and mounted it to the outside wall surface. It is about 3 feet from the ground and hidden from sight by the redwood deck. Every thing went well, no real problems.There is one issue that I feel is only fair to mention since I gave this item a five during my first review. (I would still give it a 5). This is not unique to this unit but is common with all tankless water heaters. This is a issue plumbers often refer to as a “cold water sandwich”. Basically it is where hot water left in the pipe from the previous use, is sandwiched between cold water that comes through the water heater during the first 5 seconds before it has heated water to your preferred temperature. This 5 seconds of cold water can be quite disconcerting during the winter if you jump into the shower and start running the water over your body. Quite a rush. You get a few seconds of warm water followed by about 5 seconds of cold water then followed by the warm water that was heated on demand. This isn’t really a problem as long as you are aware of it. I get into the shower, turn the water valve all the way over to all hot water, wait about 10 seconds, then back the water valve back down to a warm water mixture before turning on the shower. This will avoid the “cold water sandwich” when getting in the shower. Also be aware that in the mornings where usually no hot water had been turned on for hours, when you go to sink or shower you get about 8-10 seconds of cold water before the hot comes out. There are several ways to remedy this problem mechanically but after looking into this I decided it wasn’t worth the hassle. But if you can’t deal with this issue there are small 1 gallon water heater that can be installed and the first gallon of water is always from the tank and only when the relay is kicked in to release hot water from the tankless does the 1 gallon tank refill and heat up and stand by. This does require a reheating the same water over and over again if no one has used hot water in a while. One other technique I have had described to me, but have no personal knowledge of, is some kind of recycle valve that keeps the water in the pipes hot all the time. I’m not really sure how it works. Maybe someone who is a plumber may want to take on this issue for further discussion, but for my home we just learned very quickly that you don’t turn on the shower until the hot water has been running for 8-10 seconds. This is something I am willing to live with primarily due to the fact that my natural gas bill has dropped to half of what it used to be. Since nothing else has changed in my home, it has to be due to the tankless water heater. One other phenomena worth mentioning is that my water bill has gone up a bit, my best guess about that is that people tend to take longer showers when they know the hot water is endless. But, at least in my part of the country water is significantly cheaper than natural gas. Over all it is still a great product and I would never go back to a old style water heater that keeps heating the same water over and over again. That’s pretty stupid in retrospect. UPDATE 12/17/2015 The water heater has now been is service for over 2 years and is still working perfectly. No problems at all.

Thought I might have made a mistake but . . .

I had been interested in tankless water heater since seeing them in Morocco in the 80’s. I needed to replace my water heater and it seemed that the market for tankless water in US has finally matured. I looked at a number of different mfrs and models. I purchased this one because the reviews were good, it is smaller capacity (living alone I felt I didn’t need a lot) and the price seemed pretty good. When it arrived and I reviewed the installation requirements I realized that gas, water and venting requirements meant I would have to re-pipe and vent for this unit. I had a sinking feeling that maybe I made a mistake. Installation cost were at least as much as the water heater itself but by then I was all in. Since having it installed for a month I love it. It has a wall mounted controller that allows you to set water temperature. Controller also can display water in temp, water out temp and flow rate. I set the temp at 110 for a nice hot shower and only turn on the hot water, I don’t have to mix down over heated water with cold water. I set the temp at the maximum 167 when I run the dishwasher and the dishwasher finishes in half the time since it is not waiting to bring water up to temp. And if I want to wash the dishes just after taking a shower in seconds the water flow from heater is up to temp.

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Last update was on: July 17, 2019 5:35 pm

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Takagi Indoor Tankless, Natural Gas
Takagi Indoor Tankless, Natural Gas
Takagi Indoor Tankless, Natural Gas
Takagi Indoor Tankless, Natural Gas
Takagi Indoor Tankless, Natural Gas
Takagi Indoor Tankless, Natural Gas
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