Noritz NRC663-FSV-NG vs Ruud RTGH-68DVLN-3: which uses less energy?
At the medium draw pattern the Ruud RTGH-68DVLN-3 uses 123 therms a year and the Noritz NRC663-FSV-NG 127 — 4 therms (3%) less, about 42 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 medium draw pattern.
| Figure | Noritz NRC663-FSV-NG | Ruud RTGH-68DVLN-3 |
|---|---|---|
| UEF (Uniform Energy Factor) | 0.87 | 0.9 (better) |
| Energy use per year (therms) | 127 | 123 (better) |
| Max flow (GPM) | 3.4 | 3.5 |
| Installed cost range | $1,981–$2,963 | $2,122–$3,129 |
| 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 Ruud RTGH-68DVLN-3 if running cost matters most: it uses 4 therms less a year on the same test.
- Pick the Noritz NRC663-FSV-NG if the installed price matters more than the running cost: its modeled installed range is $1,981–$2,963 against $2,122–$3,129.
- 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
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Noritz NRC663-FSV-NG
Its filed figures, class position and running cost on your ZIP.
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Ruud RTGH-68DVLN-3
Its filed figures, class position and running cost on your ZIP.