Gas tankless · high draw
Navien NPE-xxS2
The Navien NPE-xxS2 line holds two certified rating sets of gas tankless water heaters, 2 model numbers sold as Navien, listed by Navien. Gas input runs from 150,000 to 180,000 Btu/h, and max flow at a 67 °F rise runs from 4.4 to 5.3 gal/min. Navien NPE-180S2 lists 4.4 gal/min, the fifth lowest of the 40 gas tankless sets (shared by three sets). Navien NPE-210S2 sits exactly on the median UEF of the 39 high-draw gas tankless sets, 0.96.
Certified as of October 27, 2026 · EPA ENERGY STAR data, public domain · Compare in the Heater finder
Size by size
| Rating set | Gas input, Btu/h | Max flow, gal/min | Share of heat ceiling | UEF | UEF rank | Therms/yr |
|---|---|---|---|---|---|---|
| Navien NPE-180S21 model number | 150,000 | 4.4 | 98% | 0.96 high | eighth highest of 39, 13 tied | 176 |
| Navien NPE-210S21 model number | 180,000 | 5.3 | 99% | 0.96 high | eighth highest of 39, 13 tied | 176 |
Share of heat ceiling: listed flow ÷ the flow the gas input could heat through 67 °F at 100% efficiency; test tolerances allow a little over 100%.
Navien NPE-xxS2: max flow against gas input
Max flow at a 67 °F rise, gal/min
Across the sizes
Moving from 150,000 Btu/h to 180,000 Btu/h of gas input lifts max flow from 4.4 gal/min to 5.3 gal/min, about 0.30 gal/min for each extra 10,000 Btu/h.
Strongest placings, size by size
| Measure | Value | Median of the group | Placing | Compared with |
|---|---|---|---|---|
| Gas inputNavien NPE-180S2 | 150,000 Btu/h | 180,000 Btu/h | third lowest of 40, eight tied | 40 gas tankless sets |
| Max flow at a 67 °F riseNavien NPE-180S2 | 4.4 gal/min | 5.2 gal/min | fifth lowest of 40, three tied | 40 gas tankless sets |
| UEFNavien NPE-210S2 | 0.96 | 0.96 | eighth highest of 39, 13 tied | 39 high-draw gas tankless sets |
| Rated gas useNavien NPE-210S2 | 176 therms/yr | 176 therms/yr | 13th lowest of 39, 11 tied | 39 high-draw gas tankless sets |
Model numbers
The line covers 2 model numbers, all certified 2023-02-23.
| Model number | Brand | Rating set | Vent | Fuel | Min flow | Certified |
|---|---|---|---|---|---|---|
| NPE-180S2 | Navien | NPE-180S2 | Power Direct Vent | natural gas or propane | 1.00 gal/min | 2023-02-23 |
| NPE-210S2 | Navien | NPE-210S2 | Power Direct Vent | natural gas or propane | 1.00 gal/min | 2023-02-23 |
Nearest certified alternatives
| Rating set | Max flow | UEF | Gas input |
|---|---|---|---|
| Rheem ECOHS160INcompared with Navien NPE-180S2 | +0.2 gal/min | ±0.00 | +7,000 Btu/h |
| Vesta VTS-150compared with Navien NPE-180S2 | +0.2 gal/min | ±0.00 | same Btu/h |
| Vesta VTP-150compared with Navien NPE-180S2 | +0.3 gal/min | ±0.00 | same Btu/h |
| Midea JSG40-24PCH-LPcompared with Navien NPE-180S2 | ±0.0 gal/min | −0.01 | same Btu/h |
| Kepler JSG48-29PCH/180Kcompared with Navien NPE-210S2 | −0.1 gal/min | ±0.00 | same Btu/h |