DoesTheMath

JOHN WOOD T-H3-DV-N 1** vs THERMALUX NRC111DV (GQ-C3257WX-FF US): which uses less energy?

At the high draw pattern the JOHN WOOD T-H3-DV-N 1** uses 182 therms a year and the THERMALUX NRC111DV (GQ-C3257WX-FF US) 186 — 4 therms (2%) less, about 40 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 JOHN WOOD T-H3-DV-N 1** THERMALUX NRC111DV (GQ-C3257WX-FF US)
UEF (Uniform Energy Factor) 0.93 (better) 0.91
Energy use per year (therms) 182 (better) 186
Max flow (GPM) 5.8 5.7
Installed cost range $2,264–$3,294 $2,169–$3,184
ENERGY STAR certified not matched not matched
DOE CCD · 2026-09-19

What it costs to run

JOHN WOOD T-H3-DV-N 1**: 182 therms a year THERMALUX NRC111DV (GQ-C3257WX-FF US): 186 therms a year

JOHN WOOD T-H3-DV-N 1** — 182 therms a year THERMALUX NRC111DV (GQ-C3257WX-FF US) — 186 therms a year

JOHN WOOD T-H3-DV-N 1** is 4 therms a year lower than THERMALUX NRC111DV (GQ-C3257WX-FF US).

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 JOHN WOOD T-H3-DV-N 1** if running cost matters most: it uses 4 therms less a year on the same test.
  • Pick the THERMALUX NRC111DV (GQ-C3257WX-FF US) if it is the one you can get installed sooner or for less — on the filed figures it has no advantage over the JOHN WOOD T-H3-DV-N 1**.
  • Neither if you need more than 5.8 GPM at the same time — neither unit lists more. Check how to size a tankless unit by GPM.

Each model on its own