Rinnai RL75iN Tankless Water Heater Reviews

Rinnai RL75iN is among the few gas tankless water heaters manufactured by Rinnai. Along with this model, the company also offers the RL75iP that works on liquid propane instead of natural gas. Granted, that’s why we see a pretty huge price margin between the two although most of the specifications remain the same. Geared toward multiple applications on mid-sized homes, the flow rate this heater can supply is published to be 7.5 gallons per minute. That should be more than sufficient to power up two to three showers all at the same time. Similar to other gas tankless water heaters, it also has received a rating from Energy Star, emphasizing its efficiency during its operation. If you plan to install Rinnai RL75iN on your respective owner, this review will help you tell if it’s worth it or not.

Rinnai RL75iN Tankless Water Heater Features :

Rinnai RL75iN Tankless Water Heater– Coming with gas input of 10,300 – 180,000 BTU
– Equipped with MC-91-1US Digital Controller
– Support for temperature settings of 98F – 140F
– Optimized for 2 to 3-bathroom houses
– Energy Star approved
– Having thermal efficiency of 0.82


While we find many manufacturers of tankless water heaters claiming their products to be suitable for whole house application, very few live up to its promise. Rinnai RL75iN is one of them. With a flow rate of 7.5 GPM, it practically has no trouble powering up all the faucets and showers in the house. Furthermore, since it is a tankless model, you no longer need to squeeze your brain to think where you have to place the huge water storage. This heater can be mounted in literally any room you want. By the way, note that although it’s a gas water heater, it still needs electricity to initiate the ignition. Once the burners are on, the water that is pumped into the unit gets heated right away.

In terms of efficiency, we’re glad that Rinnai RL75iN is nearing the capability of the expensive condensing water heaters. Commonly, gas-powered tankless water heaters on its class struggle to keep their thermal efficiency between 70% – 80%. However, RL75iN manages to outpower the competition by showing thermal efficiency of 82%. On to the display, it’s not only useful to monitor the current temperature but also capable of displaying error message whenever it detects leakage on the plumbing system. Last but not least, all consumers are backed with 12-year warranty.


On most installations, a flow rate of 7.5 GPM is more than enough to handle multiple applications simultaneously. However, for larger residents with four or more bathrooms, Rinnai RL75iN isn’t the best option. Well, it is only if you back it up with secondary heater. To avoid high cost, you can opt for the electric model and install it on a room in which hot water is rarely used. Another thing that may become your concern is the initial cost you have to afford. The unit retails for about $1,400 and estimated installed cost is more or less $2,000, which is certainly not cheap.


With all its benefits and impressive efficiency, this water heater is an ideal choice for those living on mid-sized houses. The 12-year warranty is also something you can’t resist easily. Overall, Rinnai RL75iN is one great tankless water heater, though the starting cost may put many of you off.