Venstar T3900 Explorer Residential Digital Thermostat 4H/2C Dual Fuel with WiFi or ZWave Capability

Venstar T3900 Explorer Residential Digital Thermostat 4H/2C Dual Fuel with WiFi or ZWave Capability

Item#: T3900
Availability:In Stock. Order by 2pm EST for same-business-day shipping.
  • Overview
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Note: Common wire required. If common wire not available see here for solution.

The Venstar T3900 Explorer Residential Digital Thermostat 4H/2C Dual Fuel with WiFi or ZWave Capability is a convenient and fully-functional control panel for your home heating and cooling systems. The fan, heat, and air conditioning are controllable through the thermostat, programmable for seven-day, single day, or five-and-two settings. An Energy Watch feature makes sure your system doesn't eat up too many resources while an outdoor sensor lets you adjust based on the temperature. The display features a blacklit color-coded design with large, easy-read digits. A variety of a other convenient options make this unit a must-have for any modern home.

When it comes to picking wireless devices for the smart home, your selection is typically determined by the technology used—and your budget. Not the case with the Venstar Explorer Digital Thermostat, you can actually choose how you want to connect: WiFi or Z-Wave. Just add one of Venstar’s optional wireless modules. Once connected, you can tap into each thermostat from in and outside of the house, in order to cut energy costs or just to make the house how you like it.

  • 4 Heat & 2 Cool Stages
  • Control to or monitor a 2nd temp sensor
  • Setpoint limiting
  • Adjustable deadbands & timers
  • High/low outdoor temps for the day
  • Programmable fan
  • Smart recovery
  • Dual Fuel capable
  • Controls humidification, dehumidification and reheat
  • Auto humidity option based on outdoor temperature
  • Lockout aux heat based on outdoor temperature
  • Can average 1 remote sensor with thermostat
  • Programmable extra output, mobile app accessible
  • Energy watch
  • Gas/Electric or heat pump - Mulit-stage
  • Simple as you want Operation 
    • Switchable : Programmable or Non- Programmable
    • Choose 7 day, 5+2 day or 1-day programming
    • Switchable: auto-changeover, heat or cool only 
  • Large. easy to read display
  • Scrolling display makes setup easy
  • Display can show dealer name, phone number and alerts 
  • Adjustable backlight intensity 
  • Backlit color coded buttons and legends
  • Choice of English, Spanish or French for scrolling display 
  • Bi-color LED indicates a heating or cooling demand 
  • Dry contact input
  • Outdoor sensor ready
  • Fahrenheit or Celsius display
  • Compatible with condensate overflow warning systems- lockout compressor with message on the display
  • Service alert indicators
  • Non-volatile memory
  • Keypad lock
  • Wireless connectivity with optional accessory
  • Title 24 compliant
  • ADR (Automated Demand Response) ready
  • FDD (Equipment Fault Protection) notification
  • API for 3rd party monitor & control
  • Night dimmer - to lower the display brightness in sensitive areas at night
  • Compatible with wireless Wi-Fi temperature sensor
  • Use Configurator app to easily setup Wi-Fi and thermostat settings

Venstar thermostats require a minimum of 3 wires for heat and a minimum of 5 wires for heat/cool (6 or more may be required if you have a heat pump system or staging).

Two-Wire Heat-Only Kit (ACC0436)

Document # V1 (3 Wires) | Document # V2 (4 Wires) | Document # V3 | Document # V4

If you need assistance figuring out how many wires you'll need, email us at, with a description of your HVAC system and a picture of your current thermostat wiring connections if possible. Please note that in rare cases, a manufacturer may use proprietary controls that may not be compatible with this thermostat.