Bradford White RTGS150N1 vs Navien NPE-180A2: which uses less energy?
At the high draw pattern the Bradford White RTGS150N1 uses 173 therms a year and the Navien NPE-180A2 178 — 5 therms (3%) less, about 55 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 | Bradford White RTGS150N1 | Navien NPE-180A2 |
|---|---|---|
| UEF (Uniform Energy Factor) | 0.98 (better) | 0.95 |
| Energy use per year (therms) | 173 (better) | 178 |
| Max flow (GPM) | 4.3 | 4.3 |
| Installed cost range NLR REMDB | $2,499–$3,570 | $2,358–$3,405 |
| ENERGY STAR certified ENERGY STAR | yes | yes |
| Sound level (dB) ENERGY STAR | 44 | not filed |
| On the market since ENERGY STAR | 2026-02-01 | 2021-01-01 |
| CPSC recall naming it CPSC | none on file | none on file |
DOE CCD · 2026-09-19 NLR REMDB · 2026-04-01 ENERGY STAR · 2026-09-19 CPSC · 2026-09-24
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 above.
- No CPSC recall on file names either model (list checked 2026-09-24).
- Both are ENERGY STAR certified, which requires a manufacturer warranty of at least six years; the actual term for each model is not published.
- Time on the market, as filed with ENERGY STAR: the Bradford White RTGS150N1 since 2026-02-01, the Navien NPE-180A2 since 2021-01-01. A sale date, not a lifespan.
Which should you pick?
- Pick the Bradford White RTGS150N1 if running cost matters most: it uses 5 therms less a year on the same test.
- Pick the Navien NPE-180A2 if the installed price matters more than the running cost: its modeled installed range is $2,358–$3,405 against $2,499–$3,570.
- 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
- Bradford White RTGS150N1 173 therms a year
- Navien NPE-180A2 178 therms a year