Takagi T-H3-DV-N Natural Gas Indoor Tankless Water Heater

When it comes to the question of a house with many people, the decision of which tankless hot water heater to buy becomes critical. Many tankless water heaters support 3 faucets at a time but if you are living in a cold climate like 35 degree temperature you some time cannot use more than two faucet simultaneously. Takagi T-H3-DV-N Natural Gas Indoor Tankless Water Heater comes as a solution to the ‘big need’ problem. With gas inputs of 199,000 BTU, the T-H3 natural gas indoor tankless water heater can support 4 bathrooms at warmer weather and 3 bathrooms at colder weather. This gas water heater has a highest flow rate of 10 GPM (gallon per minute) believe me I have written many reviews but this much GPM is very rare.

Takagi T-H3-DV-N Natural Gas Indoor Tankless Water Heater

Features of Takagi T-H3-DV-N Tankless Water Heater

Capable of producing Very large volume of very hot water

how tankless water heaters work

With 10GPM flow and intake of 19k BTU of natural gas you may have already guessed that this is a jumbo offer for hot water heater. Though Takagi conservatively says it covers 4 bathroom It can easily cope with 5, 6 bathroom and dish washer, washing machine simultaneously. The extra GMP only increases its capacity and ensures in a big family no one runs out of hot water at middle of the shower.


This unit comes with a long time warranty and conditional warranty on labor. For single family domestic hot water need it gives 15 year limited warranty, For commercial purpose limited warranty is for 10 years, 5 years limited parts for Residential and commercial use. There is a 6 year limited warranty on heat exchanger. Most users say it is complain free unit. SO once you have it you can enjoy it for 15-20 years and ROI will come up in 5 years by the electricity consumption bill.

Good for heavier purposes

Manufacture has made it hard enough, so if you own a beauty parlor, have a bar, small café and you want a tankless gas water heater this is the one. T-H3 is also suitable for heavier residential usages for example -if you need it for space heating or domestic re-circulation systems than it is good enough for these purposes.

Space saving

In compare to tank water heaters it is very much space saving compact and easy to fit in any nook of your house. With a dimension of 11.2 x 17.8 x 24.9 inches it is as big as a laptop.

Cost saving

With point of heating system, self modulating heating mechanism, and high energy conversion features this one is very loaded on cost cutting side. You can easily get your money back from the electric consumption reduction of first few years.


  • Sound less engine heater
  • Hours of hot water
  • Suitable for big family
  • This tank less water heater has Maximum flow rate of 10.0 GPM at 35°F temperature rise and 5.4 GPM at 70°F rise
  • Takagi T-H3-DV has an Energy Factor of 0.95 for Natural Gas
  • For convenience it includes safety feature -freeze, overheat, surge protection, and troubleshooting diagnostic codes

Cons with solution

Does not work on low sized pipe setting

Takagi T-H3-DV-N Natural Gas Indoor Tankless Water Heater needs 199,000 BTU gas inputs so traditional pipe line will not work and you will need visits to home depot for new pipes.


This is not a malfunction of the heater or your home’s pipe settings. The fact is most tank heater use 1/2" gas piping so if you have used a tank heater with gas input your pipe size is probably ½” .A heater with 200k BTU cannot run on 1/2" very far .So you need to up-size it to higher Users recommend a 3/4" upsizing will serve the purpose. Plus once you up-sized in future you can use other heater in same setting with same or lower gas input need.

Venting required

It is gas fired heater and natural gas heaters require venting, if you are installing it inside home without proper venting air will get suffocating.


It does need venting; all natural gas water heaters do so. If you use PVC pipe (as small as 3 feet long) to it venting will become effortless, odor less and heat less. You will not feel a thing even at the end face of the venting pipe. No chance of air or noise pollution exists. For venting purpose a Schedule 40 PVC, CPVC, PP, Category III stainless steel pipe are provided.

A wait for hot water

Takagi T-H3-DV-N Natural Gas Indoor Tankless Water Heater does not give you hot water right after you start the shower.


With tankless self-sensor heaters, water gets hot only after it senses a minimum flow. This feature is designed to reduce your electricity consumption. However it causes a delay in initial hot water flow. One solution water circulation pump that goes with this model and attaching it with Takagi T-H3-DV-N, this will put an end to wait for instantly hot water.

Professional installation

The water heater is recommended to be installed only by a licensed plumber otherwise in future problems Takagi will not support.


The warranty card asks you install the unit with a licensed plumber, gas installer, or contractor. If not than it may become void for availing warranty. If you are unable to find such installer, do not want to spend money on installation and confident enough about your prior DYI skills good news is it is a unit with very easy installation process.

Frequently Asked Questions

  • Q- Will support 4 washes room at a temperature of 45 degree in inlet?
  • Ans- It can support 4 bathrooms with that temperature as claimed by manufacturers.
  • Q- Does it function above 7600 feet altitude?
  • Ans-Yes it is perfectly functional up to 10,100 feet altitude.
  • Q-Can I use it at outdoor?
  • Ans- That may not be a good idea, installation would be difficult plus it is made for indoor only at outdoor may not function.


If you live at northern side of USA or in Canada, have a family that needs 4 bathrooms to be used at a time, want to save the space that your over sized tank water heater consume, and want a very efficient hot water supply than I shall recommend this Takagi Model.

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