ENVO WH-AZ03-180-LPI vs Noritz NRC711-OD-NG: which uses less energy?
At the high draw pattern the Noritz NRC711-OD-NG uses 190 therms a year and the ENVO WH-AZ03-180-LPI 197 — 7 therms (3%) less, about 66 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 | ENVO WH-AZ03-180-LPI | Noritz NRC711-OD-NG |
|---|---|---|
| UEF (Uniform Energy Factor) | 0.86 | 0.89 (better) |
| Energy use per year (therms) | 197 | 190 (better) |
| Max flow (GPM) | 4.3 | 4.3 |
| Installed cost range | $1,933–$2,908 | $2,075–$3,074 |
| 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 Noritz NRC711-OD-NG if running cost matters most: it uses 7 therms less a year on the same test.
- Pick the ENVO WH-AZ03-180-LPI if the installed price matters more than the running cost: its modeled installed range is $1,933–$2,908 against $2,075–$3,074.
- Neither if you need more than 4.3 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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ENVO WH-AZ03-180-LPI
Its filed figures, class position and running cost on your ZIP.
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Noritz NRC711-OD-NG
Its filed figures, class position and running cost on your ZIP.