Takagi Tankless Water Heater Reviews, Cost and Buying Guide 2021

Before you dive into the specific brand review, we highly recommend you to read our elaborate Tankless Water Heater Reviews and Tankless Water Heater Installation Cost Guide in advance. There are several crucial steps you need to take before you even start to think about the brand.

This Takagi tankless water heater review and buying guide is your comprehensive source of information for this leading brand. We’ve included all models and their specifications and a separate table of prices. Using other buying guides we’ve prepared, it’s easy to compare Takagi to Rinnai, Navien and other top brands. We’ve completed buying guides for:

Introduction to Takagi Tankless Water Heaters

Like Navien, Rinnai and Noritz, Takagi is a Japanese company. Takagi has been making innovative appliances for more than 70 years, entering the US market in 2010 in a joint business venture with AO Smith, the well-respected manufacturer of water heaters. Most Takagi and standard AO Smith tankless models are the same except for the branding.

All Takagi water heaters are gas-fired, whole-house tankless models. Some models are available in both natural gas and propane versions while many are only available in natural gas versions.

This table provides the details. Takagi tankless water heater prices are included in the table below.

ModelBTUUEF RatingsMax. GPMFuelCirculatingCondensingHeat ExchangerIndoor/OutdoorCascading
T-H3199KID .93 OD .9510NGCompatibleYesCopper/StainlessEitherYes
T-H3S180KID .95 OD .908NGCompatibleYesCopper/StainlessEitherNo
TK-540199KID .94 OD .9010EitherBuilt-inYesCopperEitherNo
T-K4190KID .80 OD .798NGNoNoCopperEitherNo

Important Note on Max. GPM: This column represents the maximum gallons per minute flow rate the heater can produce. Maximum GPM flow is achievable only when the incoming water is quite warm. The colder the incoming water is, the longer it must be heated to reach the thermostat setting on the tankless water heater, so the lower the GPM flow rate will be. In tankless water heater specifications, you’ll see information such as “Flow rate @ 70°F temp rise is 4.3 GPM.” That’s from a unit with Max. GPM of 7.5 GPM and means that if the temperature of the incoming water must be raised by 70 degrees Fahrenheit to reach the thermostat setpoint, then only 4.3 gallons per minute of hot water can be expected. For more information on this important topic, see the related section in our Tankless Water Heater Buying Guide.


  • Warranty: All Takagi gas water heaters are backed by a 15-year heat exchanger warranty, 5-year general parts warranty and 1-year labor warranty. The industry average for heat exchangers is 12 years on heat exchangers.
  • Versions: Most models come in indoor, outdoor and ultra-low NOx versions, indicated by a suffix. For example, the TK-110 is available as the TK-110C-NI (indoor), the TK-110U-I (Ultra-low NOx, indoor) and the TK-110U-E (Ultra-low NOx, outdoor/exterior).
  • Energy Star: T-H3, T-H3S, T-H3J, T-D2 and TK-540 Series are Energy Star compliant.
  • Efficiency: There are two notes here. First, Takagi uses UEF (Uniform Energy Factor) for efficiency. This is the new rating system implemented by the US DOE in 2017. Some brands still use the outdated rating of EF (Energy Factor) that is typically 2% to 4% higher than UEF. Secondly, most models offered in indoor and outdoor water heaters have the same efficiency. Where it is different, we designate it with ID for the indoor unit and OD for the outdoor unit.
  • Heat exchanger: The copper/stainless heat exchangers are an alloy of the two metals rather than containing parts made of one or the other.

Takagi Tankless Water Heaters Features Analysis

All condensing models have a 316L stainless steel secondary heat exchanger to transfer heat from combustion gases to pre-heat incoming water. The stainless steel is more resistant to corrosion than other metals.

Models that come with a remote control standard include T-H3, TK-110 ultra-low NOx, TK-510 ultra-low NOx, T-D2, T-H3J, T-H3, T-K4, T-KJr2 and T-H3S. A Takagi remote is an optional accessory for all other models. There are several versions, and they cost $80-$130 from various sellers.

Multiple Takagi units can be linked together to provide a large volume of hot water.

Some models are certified for elevations to 10,100 feet, higher than the 8,400 feet many tankless models are rated for. High-elevation models include the T-H3, T-H3S and T-H3J.

There are no WiFi Takagi water heaters.

How Takagi Water Heaters Compare to Other Tankless Brands

Fewer Takagi water heaters suffer serious mechanical problems in the first decade than any other brand. The rate is about 10%. That’s a tribute to the brands excellent design and build quality. Since faulty installation accounts for many of the failures, it’s important to have a licensed plumber with good experience install your tankless water heater.

More models come standard with a remote than from any other brand. You might use the remote regularly to adjust temperature set point, but you also might find the remote an extra expense you don’t get much use from.

Takagi Tankless Water Heater Prices

This table shows current, accurate prices for all Takagi tankless water heater models. The price variation for each model reflects a range of local and online sellers. Propane models may cost more than natural gas models. Some outdoor models cost more than indoor models. Many sellers offer free ground shipping, but it might be an additional cost from some retailers.

Takagi Models
Unit Cost Only

Takagi Tankless Water Heater Installation Cost and Factors

Gas water heater installation cost is about $1,000 to $1,500 based on several factors including:

  • Whether new gas line must be run
  • Whether a recirculation pipe is installed to provide hot water more quickly at designated outlets
  • How the unit is vented, and materials used (indoor units)
  • Whether an existing unit must be removed and disposed of

Takagi warns that the warranty is voided if the unit is not professionally installed. Hiring a licensed contractor for the job also reduces the potential for injury from shock, a gas explosion or carbon monoxide leak.

You’ll get the lowest installation estimates when you request them from several installers that know they’re competing. If you’d like to take the hassle out of getting estimates, our Free Local Quote offer makes it easy. Fill out a short form, and you’ll receive written offers from top installers in your area. They are licensed and prescreened to ensure your water heater is installed by an experienced professional. There is no cost or obligation for using the service.

1 thought on “Takagi Tankless Water Heater Reviews, Cost and Buying Guide 2021”

  1. I own a small [1,200 sq ft] house in Santa Monica. One shower; low flow fixtures and clothes washer. Probably 6.6 to 8.0 gpm.

    Am interested in installation price – energy star, condenser – Takagi or Rennai outdoor tankless. Must not void warrantie. Gas service is 1/2 inch; straight off meter, 10 to 12 foot distance. Don’t expect to get circulating pump. Would purchase directly from you, but expect to buy from Amazon given their prices.




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