Navien · NPE-S2 Tankless Water Heaters (DHW)
Navien NPE-150S2
The Navien NPE-150S2 is a condensing tankless water heater — a DHW-only appliance, not a boiler — firing 18,000 to 120,000 BTU/h at 0.93 UEF with up to 6.8 GPM at a 35°F rise.
Key figures
- Max input
- 120 MBH
- Max CSA output
- —
- AFUE
- —
- Min input
- 18 MBH
Input is gas energy consumed; output is heat delivered. Never size from input alone.
Navien NPE-150S2 in practice
The NPE-150S2 is a condensing tankless water heater in Navien's NPE-S2 line. the NPE-2 Specification Sheet prints an input range of 18,000 to 120,000 BTU/h and a Uniform Energy Factor of 0.93; the official product page publishes up to 6.8 GPM at a 35°F (19.4°C) temperature rise. It heats domestic hot water on demand and has no hydronic heating circuit.
The unit weighs 62 lb in a 17.3 W × 27.4 H × 13.2 D in cabinet, connects on 3/4" NPT water and gas lines, and is installed indoor or outdoor wall-hung. Field recirculation options per the NPE-2 installation manual. As a condensing appliance it produces acidic condensate that must be managed per the installation manual.
The NPE-2 line is sold on navieninc.ca with Canadian product pages and manuals, so Canadian availability is recorded as available. For homes that need space heating as well as hot water, Navien's combi boilers (NCB-H, NFC-H) are the boiler products; a tankless water heater such as the NPE-150S2 covers domestic hot water only and is sized on peak hot-water demand, not on a building heat-loss calculation.
Best suited to
- Domestic hot water at up to 120,000 BTU/h input
- 0.93 UEF condensing operation with 6.8 GPM maximum flow at a 35°F rise
- Installations calling for a DHW-only appliance (indoor or outdoor wall-hung)
Applicability and support
- Model number
- NPE-150S2
- Canadian availability
- available
- Production status
- current
- ROMA supplies
- Confirmed at consultation
- ROMA services
- Confirmed at consultation
- Warranty
- Not verified
Where ROMA provides on-site service
On-site service is currently offered in Greater Vancouver, BC, including Vancouver, Burnaby, Richmond, Surrey, Coquitlam, North Vancouver, West Vancouver, New Westminster, Port Coquitlam, Port Moody, Delta, Langley, Maple Ridge, Abbotsford, Chilliwack, White Rock, Pitt Meadows, Tsawwassen, Anmore, Lions Bay, Belcarra, Bowen Island, Mission. Everything else on this site is reference information you can use anywhere in Canada.
Specifications
Published specifications
Values as published by Navien. Units are shown with every value; notes flag conflicting sources or missing figures.
| Specification | Value | Note |
|---|---|---|
| Input | ||
| Input, minimum | 18 MBH | 18,000 BTU/h, per the NPE-2 Specification Sheet. |
| Input, maximum | 120 MBH | 120,000 BTU/h, per the NPE-2 Specification Sheet. |
| Efficiency | ||
| Uniform Energy Factor (UEF) | 0.93 UEF | 0.93 UEF (NG and LP) per the NPE-2 Specification Sheet; UEF is a dimensionless efficiency factor, not an AFUE percentage. |
| Domestic hot water | ||
| Maximum flow rate at 35°F (19.4°C) rise | 6.8 GPM | As printed on the official product page's temperature-rise table. |
| Water connections | 3/4" NPT | Hot and cold water connections per the official specification sheet. |
| Physical and connections | ||
| Weight | 62 lb | As printed on the official product page. |
| Width | 17.3 in | |
| Height | 27.4 in | |
| Depth | 13.2 in | |
| Gas connection | 3/4" NPT | |
| Operating limits and other | ||
| Technology | condensing tankless water heater | Recorded as a DHW appliance: this model is not a boiler and has no space-heating circuit. |
| Recirculation | Field recirculation options per the NPE-2 installation manual | |
| Fuel | Natural gas or propane | All NPE-2 models are field convertible from NG to LP per the product pages; conversion is licensed gas work. |
| Installation | Indoor or outdoor wall-hung | |
| Approvals | CSA; NSF/ANSI 5; SCAQMD 1146.2 (NOx < 20 ppm); AHRI listed per model | As printed on the official product pages. |
Alerts documented for this model
None documented yet.
Frequently asked questions
Is the Navien NPE-150S2 a boiler?
No. The NPE-150S2 is a condensing tankless water heater (DHW-only). It has no space-heating circuit; Navien's combi boilers are the NCB-H and NFC-H series.
What is the input range of the NPE-150S2?
the NPE-2 Specification Sheet prints 18,000 to 120,000 BTU/h, 0.93 UEF and up to 6.8 GPM at a 35°F temperature rise.
Where is the NPE-150S2 available?
The NPE-2 line is sold in Canada: navieninc.ca hosts product pages, manuals and specification sheets for every model, and all NPE-2 units are field convertible between natural gas and propane.
Questions about the Navien NPE-150S2?
Describe what the boiler is doing and get a straight answer about the next step.
On-site service in Greater Vancouver, BC. ROMA lists “Open 7 days” on its site; call to confirm same-day availability.
Sources and verification
- Navien — NPE-S2 series · accessed September 9, 2026
- Navien — NPE-150S2 product page · accessed September 9, 2026
- NPE-2 Specification Sheet (EN) · accessed September 9, 2026
Facts checked September 9, 2026. Last updated September 9, 2026. Technical reviewer: not yet assigned.