Rinnai Vs. Takagi: Which Tankless Water Heater Is Better?

Recently I wrote an article comparing Rinnai’s and Navien’s tankless water heaters. Now, I want to pin Rinnai against another brand: Takagi.

While Takagi claims to be the first company to bring tankless technology to North America, most plumbers I work with install Rinnai. In fact, many haven’t even heard of Takagi, and are less likely to put them in a customer’s home.

That being said, Takagi deserves a fair chance. We’ll compare Rinnai’s RUR199iN against Takagi’s T-H3-DV-N. Both are 199,000 BTU water heaters, offer 15-year limited heat exchanger warranties, and can handle multiple showers.

A UEF of .93 is one of the best ratings you’re going to get out of any gas-fired water heater, and puts the T-H3-DV-N right up there with Rinnai. The rating was certified by the Air Conditioning, Heating, and Refrigeration Institute (AHRI).

One of the interesting features of this model is its primary heat exchanger. On average, copper’s thermal conductivity is 20 times that of stainless steel. This suggests the T-H3-DV-N would heat water much faster and more efficiently than the RUR199iN, which has a stainless steel heat exchanger.

Still, there’s one potential disadvantage the T-H3-DV-N’s heat exchanger would have in this regard: copper is far less resistant to corrosion.

The primary heat exchanger is made of HRS35 commercial-grade copper. Takagi states that this alloy contains “additive elements that make it much stronger and harder than standard C1220 copper used in most other heat exchangers.” Those elements include small amounts of cobalt, tin, zinc, nickel, and phosphorous.

I couldn’t find any other company that uses HRS35 copper for their primary heat exchangers. While I commend Takagi for integrating the alloy into their design, it leaves me with a couple of questions:

If the T-H3-DV-N can handle three showers running simultaneously (assuming a ground water temperature of 40° Fahrenheit), that’s not bad. Again, I’ve personally not seen a T-H3-DV-N installed in the field (or any Takagi, for that matter), so I can’t make a personal testament to its performance.

Thankfully, we have Amazon for that, where it garnered 4.2 out of 5 stars. The only common complaint I found among homeowners was an ignition failure. Either the high-limit switch or the ignitor had to be replaced in a couple of instances. What’s concerning is that these issues occurred within 20 months of installation.

All-in-all Takagi’s installation seems pretty straightforward. From what I’ve seen in the manual, the T-H3-DV-N provides easy connection to all ports: the gas valve, hot and cold water tappings, and condensate drain port don’t seem to be on top of each other. That goes a long way.

The T-H3-DV-N does specify a minimum 3” vent pipe of up to 70’. This assumes that you have a straight shot from the intake and exhaust port to the outdoors. That never happens. For example, if I have to use just 4 fittings to vent the appliance, I can only use 3” pipe up to 50’. Otherwise, I have to increase to 4”.

Possessing a UEF of .93, the Rinnai RUR199iN comes with a 15-year warranty on its stainless steel heat exchanger. It also covers other parts for up to five years. Unlike Takagi, Rinnai also offers a 1-year warranty for labor.

One thing you’ll notice is that Takagi has a huge price advantage over the RUR199iN. While I couldn’t find it listed on Supplyhouse.com, Big Frog Supply offers the unit at $2,178.75. That’s a $1,100 difference between the two.

That being said, “you get what you pay for.” Out of the three brands of tankless water heaters I install (Navien and Bosch being the other two), I’ve had fewer issues with the Rinnai. Over the past year, I haven’t had any.

To reiterate my earlier comment: I rarely get complaints about the RUR199iN. In fact, I can only think of one instance in which the unit failed to turn on, but that was due to an issue with the customer’s propane tank.

If we’re going to compare apples to apples, the RUR199iN garnered a 4.4 out of 5 stars from Amazon customers. Homeowners often complain about Rinnai’s mobile app, control r™:

Referencing Rinnai’s ground water temperature map, the RUR199iN has somewhat of a slight edge over the Takagi. At 35° F, the water heater can run three showers simultaneously. Takagi doesn’t even list its performance at 35° F. What’s more, the RUR199iN can deliver these showers at 4.4 gallons per minute (GPM)

Those living in warmer climates, with a ground-water temperature of 72° F, can enjoy six showers simultaneously at 7.9 GPM.

As noted in my previous article, recognize that the RUR199iN (like any tankless system) will deliver a “cold water sandwich.” This is because the system holds a small amount of cold water in the water heater when it isn’t running. When you turn on the pressure to your faucet, the cold water leaves the heat exchanger and goes out your hot side.

Related Questions

Is A Tankless Water Heater Better Than A Tank-Type?

This really all comes down to personal preference, but the market is trending toward tankless systems. Homebuyers either look for tankless or hybrid-electric tanks when shopping for new homes.Some of the old-school plumbers will say that tank-type water heaters will last longer than tankless units. That was true 20 years ago, but not today. Unfortunately, they don’t make them like they used to. I can say that indirect-heated tank-type water heaters are the most reliable. HTP offers lifetime warranty on their indirect products.Tankless systems do have the following advantages:

If I were to choose between these two units, I’d stick with the Rinnai – simply because I’ve installed the system before and think it’s reliable.

That being said, I’m not one to venture away from a brand I trust to one with which I have no experience. If you’re interested in the Takagi, find a licensed plumber who has experience installing them. They’ll have a better idea of its in-field capabilities than myself.