DoesTheMath

RELIANCE WATER HEATERS T-H3M-DV-N 1** vs Ruud RTGH-68DVLN-3: which uses less energy?

At the medium draw pattern the RELIANCE WATER HEATERS T-H3M-DV-N 1** and the Ruud RTGH-68DVLN-3 use the same energy, 123 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 medium draw pattern.

Filed and computed figures
Figure RELIANCE WATER HEATERS T-H3M-DV-N 1** Ruud RTGH-68DVLN-3
UEF (Uniform Energy Factor) 0.9 0.9
Energy use per year (therms) 123 123
Max flow (GPM) 3.3 3.5
Installed cost range $2,122–$3,129 $2,122–$3,129
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 RELIANCE WATER HEATERS T-H3M-DV-N 1** if its price or availability suits you — on energy the two are level.
  • Pick the Ruud RTGH-68DVLN-3 if you run more fixtures at once: it lists 3.5 GPM against 3.3.
  • Neither if you need more than 3.5 GPM at the same time — neither unit lists more. Check how to size a tankless unit by GPM.

Each model on its own