Canada-wide gas boiler information · On-site service in Greater Vancouver, BC
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Comparison
Verdict in brief
The NPE-210S2 and NPE-240S2 are the two largest standard (S2) tankless water heaters, both 0.96 UEF and 73 lb. The 240S2 raises input from 180,000 to 199,900 BTU/h and flow at a 35°F rise from 10.1 to 11.2 GPM; both share the same cabinet and connections.
Published manufacturer figures. Input and output are kept separate; blanks mean the manufacturer did not publish that value.
| Specification | Navien NPE-210S2 | Navien NPE-240S2 |
|---|---|---|
| Input, minimum | 12 MBH | 13.3 MBH |
| Input, maximum | 180 MBH | 199.9 MBH |
| Uniform Energy Factor (UEF) | 0.96 UEF | 0.96 UEF |
| Maximum flow rate at 35°F (19.4°C) rise | 10.1 GPM | 11.2 GPM |
| Weight | 73 lb | 73 lb |
The NPE-210S2 and NPE-240S2 top the standard S2 line of condensing tankless water heaters, both at 0.96 UEF and both DHW-only appliances without the A2's buffer tank and recirculation hardware. They share a 12,000/13,300 BTU/h minimum fire split — the 240S2's slightly higher floor is immaterial at household draw rates.
The difference is the ceiling: 180,000 against 199,900 BTU/h of input and 10.1 against 11.2 GPM at a 35°F (19.4°C) temperature rise. For homes with heavy winter demand or multiple simultaneous fixtures, the 240S2's extra flow is the reason to choose it; otherwise the two behave alike.
Both measure 17.3 W x 27.4 H x 13.2 D in, weigh 73 lb, connect on 3/4" NPT water and gas lines, install indoors or outdoors and are field convertible from natural gas to propane. Neither is a boiler — where space heating is also needed, a combi or a separate boiler is required.
Navien
The Navien NPE-210S2 is a condensing tankless water heater — a DHW-only appliance, not a boiler — firing 12,000 to 180,000 BTU/h at 0.96 UEF with up to 10.1 GPM at a 35°F rise.
Navien
The Navien NPE-240S2 is a condensing tankless water heater — a DHW-only appliance, not a boiler — firing 13,300 to 199,900 BTU/h at 0.96 UEF with up to 11.2 GPM at a 35°F rise.
Yes. Both print 0.96 UEF on the official product pages.
11.2 GPM against 10.1 GPM at a 35°F (19.4°C) rise, with maximum input rising from 180,000 to 199,900 BTU/h.
No. Both are condensing tankless water heaters for domestic hot water only. Navien's combi boilers are the NCB-H and NFC-H series.
A consultation includes a heat-loss review so the size is right the first time.
On-site service in Greater Vancouver, BC. ROMA lists “Open 7 days” on its site; call to confirm same-day availability.
Sources and verification
Facts checked September 9, 2026. Last updated September 9, 2026. Technical reviewer: not yet assigned.