DoesTheMath

FRIEDRICH RTGH-68DVLN-3 vs Noritz NRC663-FSV-NG: which uses less energy?

At the medium draw pattern the FRIEDRICH 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.

Filed and computed figures
Figure FRIEDRICH RTGH-68DVLN-3 Noritz NRC663-FSV-NG
UEF (Uniform Energy Factor) 0.9 (better) 0.87
Energy use per year (therms) 123 (better) 127
Max flow (GPM) 3.5 3.4
Installed cost range $2,122–$3,129 $1,981–$2,963
ENERGY STAR certified not matched not matched
DOE CCD · 2026-09-19

What it costs to run

FRIEDRICH RTGH-68DVLN-3: 123 therms a year Noritz NRC663-FSV-NG: 127 therms a year

FRIEDRICH RTGH-68DVLN-3 — 123 therms a year Noritz NRC663-FSV-NG — 127 therms a year

FRIEDRICH RTGH-68DVLN-3 is 4 therms a year lower than Noritz NRC663-FSV-NG.

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 FRIEDRICH 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