Navien- Condensing Heating Boiler - 150,000 BTU - NHB-150H

Navien- Condensing Heating Boiler - 150,000 BTU - NHB-150H

The Navien NHB-150H is a high-efficiency condensing wall-hung boiler designed for indoor residential and light commercial heating. It delivers up to 95% AFUE with a 15:1 turndown ratio, providing precise temperature control and energy savings. Compact and wall-mounted, it measures 17.3" wide by 23.8" high and 12.8" deep, weighing 80 pounds. The boiler supports forced draft direct venting with flexible vent pipe options and lengths, allowing versatile installation.

This model includes advanced user controls and a built-in 3-zone controller to simplify multi-zone heating systems. Safety is prioritized with multiple built-in detectors and sensors, while certification to Energy Star and other standards ensures reliability. The NHB-150H is field convertible for use with natural gas or propane, meeting diverse installation needs.

Features

• 95% AFUE efficiency with 15:1 turndown ratio
• Field convertible between natural gas and propane
• Electronic ignition system
• Stainless steel primary and secondary heat exchangers
• Built-in 3-zone controller for zone valves or pumps
• Vent compatible with 2" or 3" PVC, CPVC, polypropylene, and special gas vent piping
• Maximum vent length: 2" up to 65 feet, 3" up to 150 feet
• Compact wall-hung design: 17.3" W x 23.8" H x 12.8" D; 80 lbs
• Advanced controls with backlit interface, click-wheel, and setup wizard
• Safety devices including flame rod, air proving switch, gas valve and ignition detectors, high limit switches, and vent installation detector
• Zero clearance to combustibles
• Certifications: Energy Star, CSA B149.1, ASME H, ANSI Z223.1

Applications

• Residential and light commercial space heating
• Multi-zone hydronic heating systems
• Installations requiring compact, wall-mounted boilers
• Retrofits and new construction
• Systems needing flexible venting and fuel options

What our Experts Think

• High-efficiency hydronic heating core system
  The Navien NHB-150H is a condensing heating boiler rated up to 150,000 BTU/h, designed specifically for space heating applications in residential and light commercial hydronic systems.
• Built for maximum efficiency and fuel savings
  It uses dual stainless steel heat exchangers and modulating combustion technology to achieve up to ~95% AFUE efficiency, significantly reducing energy waste compared to non-condensing boilers.
• Excellent modulation control for comfort stability
  With a turndown ratio up to 15:1, it adjusts output precisely to demand, helping reduce short cycling and improve temperature consistency throughout the heating season.
• Installer-friendly integrated system design
  Includes built-in zoning control and pump/valve management, allowing direct control of multiple heating zones without extensive external control hardware.
• Flexible venting for real-world installations
  Supports 2” PVC venting up to ~65 ft and 3” venting up to ~150 ft, giving installers strong flexibility for both new construction and retrofit applications.
• Smart controls for easier commissioning
  Features an LCD interface with setup wizard and intuitive navigation, making configuration, diagnostics, and servicing more efficient for technicians.
• Durable, service-focused construction
  Built with stainless steel heat exchangers and robust internal components, designed for long-term reliability in closed-loop hydronic systems.

Q&A

Q: What is the Navien NHB-150H (150,000 BTU) Condensing Heating Boiler used for?
A: It is a high-efficiency wall-hung condensing boiler designed for space heating in residential and light commercial hydronic systems, such as radiators, baseboards, and radiant floor heating.

Q: What is its heating capacity?
A: It provides up to 150,000 BTU/h input with an AHRI net output around 120,000–138,000 BTU/h, depending on system conditions.

Q: How efficient is the NHB-150H?
A: It operates at about 95% AFUE efficiency, using condensing technology to recover heat and reduce fuel consumption.

Q: What technology does it use?
A: It features dual stainless steel heat exchangers, modulating combustion, and a high turndown ratio (up to 15:1) for improved efficiency and reduced cycling.

Q: Where is it typically installed?
A: It is used in indoor hydronic heating systems for homes, apartments, and light commercial buildings with multiple heating zones.

Q: What makes it a condensing boiler?
A: It captures additional heat from exhaust gases by condensing water vapor, improving efficiency and lowering energy costs compared to non-condensing boilers.

Q: Why choose the NHB-150H?
A: It offers high efficiency, compact wall-hung design, strong modulation for zoning systems, and reliable stainless steel heat exchanger construction, making it ideal for modern hydronic heating setups.

Maintenance Tips

• Annual professional service: Inspect burners, heat exchangers, ignition system, and safety controls to maintain peak efficiency.
• Flush closed-loop system: Remove sludge/magnetite buildup to protect circulation pumps and maintain steady heat output.
• Check system pressure: Ensure proper hydronic pressure to prevent air issues, noise, or heating loss.
• Inspect air separator & vents: Remove trapped air that can reduce circulation efficiency or cause uneven heating.
• Clean inlet strainers (if installed): Prevent debris from restricting flow through the heating loop.
• Verify pump operation: Ensure smooth circulation across all zones without cavitation or short cycling.
• Inspect expansion tank: Confirm correct pre-charge to avoid pressure swings and relief valve discharge.
• Check venting system: Keep PVC or approved vent lines clear and properly sealed for safe combustion.
• Test safety devices: Verify high-limit switches, flame detection, and gas valve operation.
• Seasonal startup check: Before winter, confirm ignition reliability, temperature rise, and zoning response.