Endless Hot Water: Takagi Heaters

Takagi HeatersTakagi water heaters do not have tanks, instead they heat water instanteously using a gas burner. They are efficient and powerful — even the smallest heater, the Takagi T-KJr., can produces 180 gallons of hot water in an hour, but weighs only 30 pounds and is 20 inches high. They run on propane or natural gas.

Computer controlled electronic ignition allows the heater to operate without a pilot light and save up to 50% off utility costs. Prices range from $600-$1000. The heaters also have powered ventilation, computer-modulated gas flame for steady output temperatures and the industry’s best energy factor of 0.84

Takagi heaters can be used with solar preheated incoming water — only adding additional heat as needed to meet a set output temperature.

Available from: Tankless Water Heaters or Real Goods

Here are some advantages and disadvantages of tankless water heaters from the California Energy Commission.

Here’s a short new story on Takagi heaters: ABC News

17 thoughts on “Endless Hot Water: Takagi Heaters”

  1. I purchased Schuco solar water heater, and I want to combine it w/a tankless on demand water heater.
    Im reading some coments about Takagi and Rinnai.
    What is the best unit to combine w/ solar

  2. I have owned a Takagi TK-3 Model Tankless hot water heater for almost two and a half years. It is the worst thing I had installed in my house because it has already started leaking. Takagi claims they have a five year warranty, but they want me to purchase a new water heater and send them the old one to determine if the defect is under warranty. Now that is NOT Great Customer Service, so I would definitely purchase a different brand or stick with a tank model.

  3. Heath, wonder if you can comment further on Rinnai.

    I just got off the phone with the Rinnai tech rep and he said the units modulate on in and out temperature and should work as well as any tankless units. They could have some issues if incoming water is within about 15 degrees of set point but that should not be unique to Rinnai. I would think the Rinnai units, which modulate all the way down to 15K BTU, should be better than many others, though the Takagi T-K3 does go down to 11K.

    On the other hand, one installer I asked said the factory rep told them the Rinnai units would not work with solar preheated water.

    In the literature I’ve found, the only manufacturer that I’ve seen explicitly assert solar compatability have been a few of the Bosch units.

    I’ve got a low pressure well, which is another concern. Bosch recommends 40 lbs minimum for a well. I see various comments about other units getting “squirrely” which I can’t imagine is a good thing. Would sure be nice to see a definitive review of tankless units installed on well pumps with solar.

  4. Karl is incorrect. I sell solar water heating systems everyday and constantly address the tankless issue. Rinnai heaters really don’t work that well with solar. Takagi and Noritz are the way to go.

  5. Takagi and Rinnai manuals both say that it takes 4-6 seconds from the time the flow sensor (water tap turned on) detects flow to full up firing of the unit with output at the set temperature. This 6 seconds of water flow will be cold even if there’s warm water in the pipes. That’s the sandwich. Only a small holding tank would prevent it (as suggested in the Rinnai Manual).

  6. Karl:

    Why would one manuf. have a much greater problem with water sandwich than another?
    I talked to 3 manuf’s concerning water sandwich and got 3 different answers. Depending on the stats of my house and distance the sandwich period could be from 3 seconds to over 45 seconds. Is the water from the sandwich warm or on the cold side
    depending on the length of time you had the shower off while soaping up or whatever?
    One person in the engineering dept. said that the water in the line would probably not get cold for at least 10 minutes, maybe more. A plumber told me that the water sandwich water would be cold. Which is it?
    Wehn you turn on the water in the shower for the second time, having waited 10 minutes say, what temp. water will I get? I live in CA and the pipes go under the house.


  7. Solar Evacuated Tubes: Free Hot Water

    For solar water heating in your home, there are basically two types of solar collectors: conventional flat-plate collectors and evacuated tube collectors. Evacuated tubes have a number of advantages: the work on overcast days, in colder weather, and th…

  8. Can anyone comment on how the Paloma brand of tankless heaters compares to these (Takagi, Rinnai, Bosch)? Pricewise, they all seem to be about the same but, we were wondering which ones have a reputation for the highest quality and dependability.

  9. I have experience with tankless water heating systems that work on gas. They really work and are very efficent.

    Only problem is the price what is about 10 times higher than electric systems with tank.

    That usually means that you get real benefit only on long run (in our country about 3 years with regular shower usage) or on very high usage – when you like to take long shower sessions or even bath.

    But when economical side is not the issue then I strongly recommend tankless systems.

    One more thing that makes tankless systems better than systems with tank is that because there is no tank then there is no problem with spoiled water that may happen when same water is too long in the tank.

    1. In the UK the Brittony 11T by Chaffoteaux was the best tankless on demand gas water heater,unfortunately they have recently stopped making them. …with balanced flue gas wall heaters proved a low maintenance long term low cost alternative to central heating(if you consider initial cost and the cost of maintaining and replaceing condensing gas boilers.)

  10. Everyone I know in Japan uses something similar to this. In fact, the whole water tank idea is unknown here. It`s just so wasteful! It seems like it would be more popular in other places, but I guess not.

  11. rinnai is the much better choice for solar applications. tiakagi has a high limit cut out that disables the unit at normal solar temperatures. rinnai also has this safety mechanism but doesn’t present problems as often. also tiakagi has a tragic cold water sandwich effect that is very irritating and wasteful of water.

    i’ve installed plenty of both of these units and recommend the rinnai continuum

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