DoesTheMath

Rheem RTGH-RH10DVLN * vs TAKAGI T-H3S-OS-N 1**: which uses less energy?

At the high draw pattern the Rheem RTGH-RH10DVLN * and the TAKAGI T-H3S-OS-N 1** use the same energy, 180 therms a year each, on the same federal test. Both are filed as a gas tankless unit, so the comparison holds; what separates them is below. Enter your ZIP to price either one on your own rate.


Side by side

Compared within one class only: models filed as a gas tankless unit at the high draw pattern.

Filed and computed figures
Figure Rheem RTGH-RH10DVLN * TAKAGI T-H3S-OS-N 1**
UEF (Uniform Energy Factor) 0.94 0.94
Energy use per year (therms) 180 180
Max flow (GPM) 5.2 5.3
Installed cost range $2,311–$3,350 $2,311–$3,350
ENERGY STAR certified not matched not matched
DOE CCD · 2026-09-19

What it costs to run

Enter your ZIP to price both units on the same rate where you live.


Reliability

Not published: Reliability, failure rates and each model’s actual warranty term.

The registries these figures come from certify energy performance under a federal test; none of them records how long a unit lasts or how often it fails, so this page does not rank the two on reliability.

What is here instead:

  • The filed efficiency, capacity and tank size of both models, side by side below.
  • The actual warranty term is printed in each model’s documentation, not in any registry.

Which should you pick?

  • Pick the Rheem RTGH-RH10DVLN * if its price or availability suits you — on energy the two are level.
  • Pick the TAKAGI T-H3S-OS-N 1** if you run more fixtures at once: it lists 5.3 GPM against 5.2.
  • Neither if you need more than 5.3 GPM at the same time — neither unit lists more. Check how to size a tankless unit by GPM.

Each model on its own