Ultra-High Efficiency Unit Heaters

Sterling’s Nexus brings gas-fired unit heaters to unprecedented levels of efficiency. Its industry leading 99%* thermal efficiency combines the latest innovations, including a tri-metal stainless steel heat exchanger and a state-of-the-art proprietary combustion control system.

Efficiency matters...not only is the Nexus the most energy efficient unit heater available, but it is also the most environmentally friendly too. Reduced emissions, low fuel utilization and a reduced carbon footprint give Nexus our green stamp of approval!

*Up to 99% maximum efficiency at full turndown, 95+% certified efficiency at high fire.

Standard Features

  • 50 - 400 MBH
  • 97% Thermal Efficiency
  • Durable Brushed Stainless Steel Cabinet
  • Tri-Metal Stainless Steel Heat Exchanger
  • Separated Or Standard Combustion All-In-One Units
  • NG/LP Single Orifice Field Conversion Kit Included
  • 2-Stage, Modulation with Room Sensing, And Outdoor/Indoor Air Reset Self Modulating Settings
  • Modbus Communication for BMS Standard
  • Full Condensing Efficiencies at All Firing Rates
  • 3:1 Full Modulation
  • Auto-Adjusts for Altitude
  • PVC/CPVC Vent Compatible
  • Multiple Voltage Configurations
  • Condensate Float Switch and Trap Standard
  • 10-Year Heat Exchanger, Flue Collector, and Burner Warranty,

Outdoor Air Reset Modulation


Units automatically vary discharge temperatures based on the outside air temperature providing seamless modulation for optimum efficiencies. By running at lower discharge temperatures subject to the outdoor temperatures, units run longer at higher efficiency resulting in less cycling, lower fuel costs, and increased occupancy comfort. As the outdoor temperature drops, discharge temperatures increase and vice versa. Outdoor Air Reset is optimal in regions with substantial daily temperature swings.

    Indoor Air Reset

    Nexus’ indoor air reset technology essentially learns the heating needs of the building by constantly monitoring run-time percentages and modulates accordingly. Indoor Air Reset allows Nexus to operate at full modulation (low fire) for as long as reasonable to maintain the heating load. By running at low fire units run longer at higher efficiency resulting in less cycling, lower fuel costs and increased occupancy comfort.


      The Nexus Control Board includes Modbus communication as a standard feature without requiring additional control modules. The control board provides feedback to the building automation system allowing for the remote monitoring of over 30 data points including unit fault codes. This allows user to know what is wrong with the unit without even entering the building

        Gas Controls

        The only fully modulating, high efficiency unit heater produced, Nexus utilizes a burner control and configuration that allows a 3:1 turndown for precision discharge temperature control, with this technology units run more efficiently for a longer period of time with reduced cycling. Competitors use in-shot burners and only offer 1:1 on/off configuration that often times result in over/under heating the occupied space and increased wear and tear on the equipment with constant cycling.



          Premium performance in the safest possible way… All units use Sterling’s proprietary combustion control platform which guarantees clean combustion regardless of the operating conditions. Combustion is constantly monitored through Nexus’ electronic air/fuel coupling control platform, consistently maintaining safe levels of emissions.



            Units auto-adjust the air/fuel mixture for altitude adjustments so there are no field adjustments required. Nexus also has SafeSense technology for blocked inlet/flue conditions. Units will maintain clean combustion in a partial blockage situation without decreasing performance insuring safe combustion at all times. In a situation of unsafe combustion, units will shut themselves down until the necessary corrective actions are completed.


              Heat Exchanger

              Nexus’ tri-metal heat exchanger is the most advanced on the market today. Engineered for maximum efficiency; our tri-metal hybrid design utilizes all of today’s technologies for optimum heat transfer. A unique combination of metals and tube configurations scrub every last bit of heat energy from the combustion process. The use of stainless steel with high conductivity brass and even higher conductivity aluminum all working in conjunction with turbulators to improve the heat transfer from the hot flue gases to the bi-metal fins produces up to 95+% operating efficiency at full fire

                Sophisticated Styling

                Nexus brings a whole new look to the unit heater arena with a beautiful commercial-grade brushed stainless steel jacket with contrasting black trim. Its corrosion resistant exterior and double-wall construction provide both durability and increased efficiency through reduced heat loss…appealing and functional.


                  In today’s marketplace where time is money, Nexus is designed to be user and service friendly. Whether natural or LP gas, conversions are simple and quick through a single orifice conversion with kits included as a standard feature. Multiple operating voltages, flexible venting options and some of the longest throws in the segment make Nexus the only choice for any application. Units can operate in a single unit mode, multi-unit networks or linked to a building management system with seamless control communication.


                    All the Literature associated with the Nexus


                    For additional items browse the full Literature library at the link below.


                    Performance, Materials and Features for each Nexus capacity model.








                    MBH Input50 MBH100 MBH150 MBH200 MBH300 MBH400 MBH
                    MBH Output48,600 MBH96,000 MBH143,000 MBH192,000 MBH285,000 MBH384,000 MBH
                    Thermal Efficiency97%96%95%96%95%96%
                    Air Temp Rise57°F55°F50°F55°F55°F55°F
                    Turn Down Ratio3:13:13:13:13:13:1
                    Modulating ControlYesYesYesYesYesYes
                    Entering Airflow (CFM @ 70°F)790 CFM1616 CFM2661 CFM3232 CFM4848 CFM6464 CFM
                    Outlet Velocity (FPM)697 FPM977 FPM928 FPM1127 FPM1101 FPM1114 FPM
                    Heat Throw @ 20' Mounting HeightN/A150'N/A150'150'150'
                    Combustion Air Intake Size2"2"2"3"4"4"
                    Combustion Air Intake MaterialPVC/CPVCPVC/CPVCPVC/CPVCPVC/CPVCPVC/CPVCPVC/CPVC


                    Motor HP1/141/21/121/211
                    Motor Count2 Motor(s)1 Motor(s)2 Motor(s)2 Motor(s)2 Motor(s)2 Motor(s)
                    Motor RPM1,500 RPM1,500 RPM1,500 RPM1,500 RPM1,625 RPM1,625 RPM


                    Flue Size2"2"2"3"4"4"
                    Venting CategoryIVIVIVIVIVIV


                    Fuel TypeNG/LPNG/LPNG/LPNG/LPNG/LPNG/LP
                    Min Gas Pressure Natural5 in wc5 in wc5 in wc5 in wc5 in wc5 in wc
                    Min Gas Pressure LP8 in wc8 in wc8 in wc8 in wc8 in wc8 in wc
                    Max Gas Pressure Natural14 in wc14 in wc14 in wc14 in wc14 in wc14 in wc
                    Max Gas Pressure LP14 in wc14 in wc14 in wc14 in wc14 in wc14 in wc
                    Gas Connection Size.5".5".5".5".75".75"


                    Condensate TrapYesYesYesYesYesYes
                    Condensate Discharge Size.75".75".75".75".75".75"
                    Condensate Production (gal/hr).41 gal/hr.73 gal/hr1.06 gal/hr1.38 gal/hr1.71 gal/hr3 gal/hr


                    Supply Voltage Phase115V - 1PH115V - 1PH115V - 1PH115V - 1PH115V - 1PH115V - 1PH
                    Full Load Amps10.8010.3017.6017.6031.2031.20
                    Motor Amps (total fan motor amps)5.206.0012.0012.0022.0022.00


                    Weight120 lbs180 lbs209 lbs260 lbs323 lbs385 lbs

                    Clearance Service/Combustible

                    Air Intake Side18"18"18"18"36"36"
                    Access Side18"18"18"18"18"18"
                    Non Access Side2"6"6"6"6"6"


                    Dimensions and weights for each Nexus capacity model.



                    The Nexus is quite versitile it can be installed in a variety of applications. Here are a few key ways The Nexus can make your space more comfortable.

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