FRIEDRICH RTGH-90DVLN-3 vs THERMALUX NRC98DV (GQ-C2857WS-FF US): which uses less energy?
At the high draw pattern the FRIEDRICH RTGH-90DVLN-3 uses 182 therms a year and the THERMALUX NRC98DV (GQ-C2857WS-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.
| Figure | FRIEDRICH RTGH-90DVLN-3 | THERMALUX NRC98DV (GQ-C2857WS-FF US) |
|---|---|---|
| UEF (Uniform Energy Factor) | 0.93 (better) | 0.91 |
| Energy use per year (therms) | 182 (better) | 186 |
| Max flow (GPM) | 4.9 | 5.1 |
| Installed cost range | $2,264–$3,294 | $2,169–$3,184 |
| ENERGY STAR certified | not matched | not matched |
What it costs to run
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 FRIEDRICH RTGH-90DVLN-3 if running cost matters most: it uses 4 therms less a year on the same test.
- Pick the THERMALUX NRC98DV (GQ-C2857WS-FF US) if you run more fixtures at once: it lists 5.1 GPM against 4.9.
- Neither if you need more than 5.1 GPM at the same time — neither unit lists more. Check how to size a tankless unit by GPM.
Each model on its own
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FRIEDRICH RTGH-90DVLN-3
Its filed figures, class position and running cost on your ZIP.
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THERMALUX NRC98DV (GQ-C2857WS-FF US)
Its filed figures, class position and running cost on your ZIP.