DoesTheMath

LAARS LT150NXX1 vs RINNAI (RX160I) REU-NB2530FF-US: which uses less energy?

At the high draw pattern the LAARS LT150NXX1 uses 173 therms a year and the RINNAI (RX160I) REU-NB2530FF-US 175 — 2 therms (1%) less, about 18 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.

Filed and computed figures
LAARS LT150NXX1 RINNAI (RX160I) REU-NB2530FF-US
UEF (Uniform Energy Factor) 0.98 (better) 0.97
Energy use per year (therms) 173 (better) 175
Max flow (GPM) 4.3 4.6
Installed cost range $2,499–$3,570 $2,452–$3,515
ENERGY STAR certified yes yes
Sound level (dB) 44 not filed
On the market since 2026-02-01 2024-03-01
DOE CCD · 2026-09-19

What it costs to run

LAARS LT150NXX1: 173 therms a year RINNAI (RX160I) REU-NB2530FF-US: 175 therms a year

LAARS LT150NXX1 — 173 therms a year RINNAI (RX160I) REU-NB2530FF-US — 175 therms a year

LAARS LT150NXX1 is 2 therms a year lower than RINNAI (RX160I) REU-NB2530FF-US.

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.
  • 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 LAARS LT150NXX1 since 2026-02-01, the RINNAI (RX160I) REU-NB2530FF-US since 2024-03-01. A sale date, not a lifespan.

Which should you pick?

  • Pick the LAARS LT150NXX1 if running cost matters most: it uses 2 therms less a year on the same test.
  • Pick the RINNAI (RX160I) REU-NB2530FF-US if you run more fixtures at once: it lists 4.6 GPM against 4.3.
  • Neither if you need more than 4.6 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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