Takagi T-H3-DV-N Review


This is one heater you need to get for your house. It supplies hot water endlessly when demanded either directly or indirectly. Apart from being used as a heating appliance, Takagi T-H3-DV-N can be used with hydronic heating systems, storage tanks, recirculation systems, and radiant floor systems. T-H3S series of Takagi tankless water heater range is highly efficient and offers Ultra-Low NOx condensing technology, which lets you use 3" PVC venting and ensure 0" clearance to combustibles.  With gas inputs of about 180,000BTU, it can be termed as the perfect residential heating application that can provide hot water for 2 to three bathrooms in warmer weather and two bathrooms in colder weather. The unit’s heat exchanger tubing has been created from HRS35 copper alloy and each unit comes with a remote control and up to 10,100ft certification. It is ENERGY STAR® approved and comes with 15-year heat exchanger limited warranty and 5-year parts limited warranty for domestic users. The unit has 0.95 energy factor for natural gas, flow rate is 8.0GPM at 35degree F. It is a risk-free and very secure unit since it has built-in mechanism for preventing overheating, freeze, surge protection, and also has troubleshooting diagnostic codes.

The Pros & Cons of the Takagi T-H3-DV-N


  • Unbelievably efficient with 10GPM hot water supply
  • The unit utilizes HRS35 commercial grade copper allow, which is great for transferring heat and corrosion resistance than the regular stainless steel option
  • Unit has sleek, compact and attractive design and can be fitted just about anywhere around your house
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    Eco-friendly heater that doesn’t produces high amounts of nitrous oxide and is SCAQMD certified
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    You can easily save a lot on your monthly natural gas bills because this heater doesn’t use natural gas constantly and don’t have a storage tank
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    The unit aptly tackles the problem of delayed hot water supply that is common among most tankless natural gas heaters because it pumps hot water directly into the pipe instantly thereby curbing the waiting duration from standard 2min to just 1/2 min.


  • Though it minimizes natural gas bills and also uses lesser amount on a daily basis but when it heats the water, the amount of natural gas utilized is 4 to 5 times higher than tanked heaters. This means the unit requires specialized gas lines for handling such a high volume of natural gas
  • Need for additional components and high quality pipes increases the expenditures and hike the unit’s price
  • The fact cannot be ignored that this product from Takagi is very expensive

Installation and Specifications

Installation wise this unit is very user friendly. The package contains an illustrative user manual containing thorough step-by-step instructions for installing it. The heater is equipped with integrated controls and comes with a power cord and venting is done by Schedule 40 PVC, CPVC, PP, Category III stainless steel.  Since AO Smith is now the owner of Takagi therefore, it is necessary that you own the valve kit named AO Smith 9007604005 Isolation Valve Kit and to neutralize the acidic proportion of water in some regions users might also need to buy AO Smith 9007607005 Neutralizer Kit. However, since it is a condensing heater, so you don’t need stainless steel exhaust vents and PVC will be fine.


Assembled Depth10.7"
Assembled Height22.4"
Assembled Width17.7"
Product Depth10.7"
Product Height22.4"
Product Width17.7"
Vent diameter3"
Water Connection Size3/4"
Finish FamilyWhite
Flow Rate @ 35 F Rise (gallons/min)5.65 gal (US)/min
Flow Rate @ 45 F Rise (gallons/min)6.95 gal
Fuel TypeNatural Gas/Propane
Gas Connection Size3/4"
Gas Product TypePoint of Use
Gas TypeLiquid Propane
Maximum Temperature (F)140
Minimum Activation Rate (psi)15
Minimum Temperature (F)77
Pilot LightNo
Product Weight (lb.)59 lb
Residential/Commercial/industrial UseResidential or commercial
Total BTU199000
Water Connection LocationBottom
Water Heater FeaturesWall Mountable
Vent TypeSingle Wall

Common Problems

Takagi’s this product is although highly efficient as a condensing heater but such heater usually have the problem of generating slightly acidic condensate water. Even in this unit this problem occurs and you need to mount the device at a place where drainage is nearby since you need to drop a small hose into it. If there isn’t a drain nearby then you need to place a bucket underneath to provide outlet for the condensate. Overall, this model is excellent since many endemic problems of tankless water heaters have been eliminated in this one and the unit doesn’t cause any serious issues.


The Takagi T-H3-DV-N is an excellent tankless water heater. It does its job, and does it well, and is an improvement over the Takagi-T-KJr2-IN-NG product. That being said, the flaw in its design does hamper its efficiency somewhat, and the high installation costs must be taken into consideration whilst deciding whether or not to purchase this product.

You can buy the Takagi T-H3-DV-N on Amazon.

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