DoesTheMath

LOCHINVAR T-H3M-OS-N 1** vs RINNAI (RX130I) REU-NB2024FF-US: which uses less energy?

At the medium draw pattern the RINNAI (RX130I) REU-NB2024FF-US uses 114 therms a year and the LOCHINVAR T-H3M-OS-N 1** 122 — 8 therms (6%) less, about 75 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 LOCHINVAR T-H3M-OS-N 1** RINNAI (RX130I) REU-NB2024FF-US
UEF (Uniform Energy Factor) 0.91 0.97 (better)
Energy use per year (therms) 122 114 (better)
Max flow (GPM) 3.5 3.8
Installed cost range $2,169–$3,184 $2,452–$3,515
ENERGY STAR certified not matched yes
On the market since not filed 2024-03-01
DOE CCD · 2026-09-19

What it costs to run

LOCHINVAR T-H3M-OS-N 1**: 122 therms a year RINNAI (RX130I) REU-NB2024FF-US: 114 therms a year

LOCHINVAR T-H3M-OS-N 1** — 122 therms a year RINNAI (RX130I) REU-NB2024FF-US — 114 therms a year

RINNAI (RX130I) REU-NB2024FF-US is 8 therms a year lower than LOCHINVAR T-H3M-OS-N 1**.

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 RINNAI (RX130I) REU-NB2024FF-US if running cost matters most: it uses 8 therms less a year on the same test.
  • Pick the LOCHINVAR T-H3M-OS-N 1** if the installed price matters more than the running cost: its modeled installed range is $2,169–$3,184 against $2,452–$3,515.
  • Neither if you need more than 3.8 GPM at the same time — neither unit lists more. Check how to size a tankless unit by GPM.

Each model on its own