SGX & SSX Single Duct Retrofit Terminals

Energy-saving VAV terminals for retrofit applications

Cut energy costs by adding retrofit terminals to your commercial building with quick, simple installation—and enjoy cleaner, more comfortable air.

  • Provided with FlowStar Airflow Sensor
  • Attaches to any pre-existing constant volume unit, easily installed in round or spiral ductwork
  • Compatible with optional ZEC500 and ZEC510 direct digital controls (DDC)
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Product Overview

Looking to save energy in your commercial space? Retrofit terminals allow you to easily convert mechanical, constant-volume terminals to a variable air volume configuration. For even greater savings through precise fan volume control, ENVIRO-TEC retrofit terminals may be equipped with factory-mounted ZEC500 or ZEC510 DDC (direct digital control) units. We’re excited to offer you two VAV terminals for retrofit applications: the Model SGX Exhaust Valve with galvanized-steel construction and the Model SSX Exhaust Terminal featuring stainless-steel construction. These terminals are a great choice for exhaust flow control in critical spaces such as laboratories and industrial airflow applications as well as VAV fume hood applications utilizing face velocity controls and for general room exhaust. Both models are designed with a round inlet and outlet and are compact in size for easy installation in round or spiral ductwork. If your retrofit application calls for a stand-alone airflow measuring station, consider the Model RFT-MS. This device is a short, circular, sheet-metal sleeve that can be easily attached to any VAV terminal with a round inlet. Featuring the patented FlowStar airflow sensor, the RFT-MS is a convenient way to retrofit a building to meet today’s IAQ standards.
Product Overview



ENVIRO-TEC single-duct retrofit terminals maximize building air quality, comfort, and airflow with improved airflow measurement and damper control.


ENVIRO-TEC SGX and SSX single-duct retrofit terminals easily install to any mechanical constant-volume terminal, which allows for conversion to variable air volume (VAV).


Our retrofit SGX and SSX terminals deliver long-lasting performance through quiet, precise airflow to the occupied space.

Genuine Performance
Genuine Performance

ENVIRO-TEC products offer genuine performance advantages through unique configurations, control options, and industry-leading sound data.


  • AHRI 880- and ETL-certified and labeled to meet industry performance and safety standards.
  • Optional SQ for OSHP-OSP Seismic Certification
  • Robust inlet collar for ease in mounting and installation.
  • An integrated VAV box with direct digital controls can provide for a bundled offering with lower total installation costs.
  • Model SGX features the patented FlowStar airflow sensor on all but two sizes.
  • Both models may be ordered with a ZEC500 or ZEC510 DDC or with pneumatic controls
  • Provided with air balancing taps
  • Superior FlowStar air-measuring probe provides for lower minimum cubic feet per minute (CFM) values, which reduces energy costs and noise while maintaining comfort in the zone.
  • Standard-height and low-height units for a variety of single-duct application requirements.
  • OSHP-OSP-certified in compliance with CBC and IBC to ensure cabinet integrity throughout the installation process and seismic events.
  • A variety of sizes are available to accommodate virtually any application (SGX = 8 sizes; SSX = 6 sizes).
  • SSX includes a single-axis, multipoint averaging sensor
  • SSX model features stainless steel construction
  • 18 month Limited Warranty