Hot Water List

Gas tankless water heaters side by side

The 7 most-searched gas tankless models, with the certified figures of each.

Warmed by 67°F, the slowest gives 4.6 gallons per minute and the fastest 5.8 gallons per minute. At the high end, 5.8 gallons per minute, more than one model ties. Among these models, the Rinnai (RX160I) REU-NB2530FF-US is the one at the low end. An advertised flow sits beside the certified one for 6 of these 7 models, in the table.

Each model here was tested on the high draw pattern, one simulated day of hot water use. Model by model, each unit of energy in gives 0.93 to 0.98 units of hot water energy out. ENERGY STAR certified status goes to 6 of these 7 models.

All 7 models here may qualify for at least one rebate program. Other basic models match every figure of 3 of these 7 models. In all, the figures here belong to 13 basic models.

Every gas tankless model by efficiency and flow

Up is more flow, warmed by 67°F in the test. Right is more efficient. A UEF compares only between models tested on the same draw pattern, so the chart shows one pattern at a time, the most common first.

Very small draw pattern · 2 models
Gas tankless water heaters, very small draw pattern: efficiency and flow at a 67°F rise (gal/min) 2 models. UEF axis from 0.87 to 0.89. Highest UEF and most output: CAMMOO RV-65000B, UEF 0.89, 1.6 gal/min. CAMMOO RV-65000B UEF 0.89, 1.6 gal/min
Low draw pattern · 9 models
Gas tankless water heaters, low draw pattern: efficiency and flow at a 67°F rise (gal/min) 9 models. UEF axis from 0.81 to 0.84. Highest UEF: 2 models, UEF 0.84. Most flow: 2 models, 2.5 gal/min. 2 models UEF 0.842 models 2.5 gal/min
Medium draw pattern · 77 models
Gas tankless water heaters, medium draw pattern: efficiency and flow at a 67°F rise (gal/min) 77 models. UEF axis from 0.80 to 0.98. Highest UEF: Rinnai, (RX130I) REU-NB2024FF-US, UEF 0.97. Most flow: 3 models, 3.9 gal/min. Rinnai (RX130I) REU-NB2024FF-US UEF 0.973 models 3.9 gal/min
High draw pattern · 399 models
Gas tankless water heaters, high draw pattern: efficiency and flow at a 67°F rise (gal/min) 399 models. UEF axis from 0.80 to 0.99. Highest UEF: 5 models, UEF 0.98. Most flow: 4 models, 8.5 gal/min. 5 models UEF 0.984 models 8.5 gal/min

Compare every water heater type by efficiency

Certified figures

In order of flow, lowest first, then UEF, highest first.

Gas tankless water heaters: certified figures side by side
FigureRinnai (RX160I) REU-NB2530FF-USNoritz NCC199CDV (GQ-C3261WZ-FF US)Rheem RTGH-95DVLN-3Noritz EZ111DV (GQ-C3260WX-FF US)Navien NPE-240A2Rinnai (RX199I) REU-NB3237FF-USNavien NPE-240S2
Flow at a 67°F rise (gal/min)4.65.55.55.65.65.85.8
Advertised flow (gal/min)9.0 Lowe's, no rise stated9.2 Noritz, no rise stated9.5 Rheem, no rise stated—5.6 Navien, at a 67°F rise11.1 Lowe's, no rise stated11.2 Navien, at a 35°F rise
UEF0.970.980.930.960.950.980.96
Draw patternHighHighHighHighHighHighHigh
Recovery efficiency98%98%95%98%98%99%99%
ENERGY STARCertifiedCertified—CertifiedCertifiedCertifiedCertified
Listed models4664141
Rebate programs (may qualify)6626666
Also listed as——3 basic models2 basic models——1 basic model

UEF is the uniform energy factor. A UEF compares only between models with the same draw pattern. A range means the listed models differ. A dash means no such figure, or not listed as ENERGY STAR certified.

Also listed as

Rheem RTGH-95DVLN-3

Noritz EZ111DV (GQ-C3260WX-FF US)

Navien NPE-240S2

Each carries every figure in its column.

Every gas tankless water heater with its certified figures

Updated Oct 17, 2026 · Methodology

Not covered

  • Price, warranty, and installation.
  • Models searched for less often. Each one is on the full list.