Unit Heaters & Inline Duct Heaters


Modine cabinet unit heaters effectively make each area served an independent heating zone. Through thermostatic control of heater operations, conditions can be varied to suit diverse requirements or activities. Optional controls and outside and return-air dampers are available to provide for ventilation and recirculation of room air.

Modine cabinet unit heaters are available in a choice of two models and eight sizes to properly match units to job requirements. This versatility eliminates compromising architecture or design. Important cost savings are often realized during building modernizations, as existing piping and/or wiring can frequently be reused.

Design techniques are incorporated in every cabinet unit heater to reduce noise levels to an absolute minimum. These techniques include low blower speeds, rigid panel and cabinet construction, and sound-absorbent cabinet insulation.

Clean, uncluttered designs and compact dimensions allow Modine cabinet unit heaters to blend into any environment and minimize installation space. The standard cabinet finish is a light-tan baked polyester powder coat paint, and optional factory applied decorative colors are also available.

• One- or Two-Row, Copper Tube – Aluminum Fin Coil
• Motor with Built-In Thermal Overload Protection, 115v/60/1
• Forward-Curved Aluminum Blower Wheels
• Unit-Mounted, Solid-State Speed Control
• Permanent, Cleanable Air Filter
• Sound-Dampening Insulation on Front Panels
• Stamped Louvers


Sterling is proud of the reputation it has earned in the hydronic heating equipment market for product quality, design, innovations and customer service.

Offered in both horizontal and vertical air delivery models, Sterling unit heaters are a complete heat distributing plant, encased in an attractive, streamlined baked enamel housing. Designed for ceiling mounting, they provide a convenient, low cost method of heating warehouses, stores, factories, and other large open areas.


Suspended from the ceiling of a Factory, Box Store or Warehouse, unit heaters provide an excellent solution for Doorway Heating, Freeze Protection, Space Heating, and summer time air circulation.

• Low First Cost
• Easy to Install & Maintain
• Excellent Redundancy



Sterling Indoor Duct Furnances are 80% efficient and are designed for ducted air applications. These are typically built up systems using a separate air moving device and may be heating only or heating and air conditioning applications. All Sterling duct furnances are CSA certified for installation upstream or downstream from cooling coils (stainless steel heat exchangers are recommeded).


The Modine indoor separated combustion duct furnace was designed for use with a building’s heating, heating/cooling and make-up air systems. Modine separated combustion duct furnaces are specifically designed for buildings with hostile atmospheric conditions, such as high humidity or negative pressures. Available in 11 power exhausted model sizes, the unit covers a wide variety of applications. They have input ranges from 75,000 to 400,000 Btu/Hr and can operate on either natural or propane gas. The airflow direction can be specified when ordering the unit. The duct furnace is certified for location either upstream or downstream from cooling coils and has a drain pan that allows connection to a condensate drain line. Standard Features:

• C.S.A. certification – bearing C.S.A. logos
• ETL certification
• All units a minimum of 80% thermally efficient
• 20-gauge aluminized steel cabinet
• Certified to 3.0″ W.C. external static pressure
• Separate electrical, venting, and gas control access with fully gasket-installed doors

Optional Features:
• 409 stainless steel heat exchanger and burner
• 409 stainless steel drip pan
• Two-stage, mechanical modulation, and electronic modulation controls for either natural or propane gas
• Building management compatible gas controls for modulation control using 0 – 10 Vdc or 4 – 20 mA input
• High and/or low gas pressure switches

Catalog: 5-173* All Product Literature: Duct Furnaces & Direct-Fired Units


Duct Furnaces for space heating and replacement air applications. Suited for the following:
• Stores, Warehouses & Distribution Centers
• Providing Factories with additional heat
• Install in on roof adjacent to existing ductwork & equipment for supplying replacement air for exhaust hoods
• Combine with a Blower Cabinet for a Custom Heating (& cooling) solution
• Install for additional heat after a renovation or space addition