DoesTheMath

GSW WATER HEATERS T-H3J-DV-N 1** vs Ruud RTGH-90DVLN-3: which uses less energy?

At the high draw pattern the GSW WATER HEATERS T-H3J-DV-N 1** uses 180 therms a year and the Ruud RTGH-90DVLN-3 182 — 2 therms (1%) less, about 19 therms over ten years. Both are filed as a gas tankless unit, so the comparison holds. Enter your ZIP below to price the difference.


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 GSW WATER HEATERS T-H3J-DV-N 1** Ruud RTGH-90DVLN-3
UEF (Uniform Energy Factor) 0.94 (better) 0.93
Energy use per year (therms) 180 (better) 182
Max flow (GPM) 4.7 4.9
Installed cost range $2,311–$3,350 $2,264–$3,294
ENERGY STAR certified not matched not matched
DOE CCD · 2026-09-19

What it costs to run

GSW WATER HEATERS T-H3J-DV-N 1**: 180 therms a year Ruud RTGH-90DVLN-3: 182 therms a year

GSW WATER HEATERS T-H3J-DV-N 1** — 180 therms a year Ruud RTGH-90DVLN-3 — 182 therms a year

GSW WATER HEATERS T-H3J-DV-N 1** is 2 therms a year lower than Ruud RTGH-90DVLN-3.

DOE CCD · 2026-09-19

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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 GSW WATER HEATERS T-H3J-DV-N 1** if running cost matters most: it uses 2 therms less a year on the same test.
  • Pick the Ruud RTGH-90DVLN-3 if you run more fixtures at once: it lists 4.9 GPM against 4.7.
  • Neither if you need more than 4.9 GPM at the same time — neither unit lists more. Check how to size a tankless unit by GPM.

Each model on its own