The S1-THSU21P1S is our value minded residential LX thermostat. This thermostat can be configured to be a single day programmable or non-programmable thermostat. It can control up to 2 stages of heat and 1 stage of cooling. The S1-THSU21P1S may also display the outdoor temperature when paired with the optional LX Wireless Temperature Sensor.

As with all of the LX Series thermostats, you may program a custom message on the scrolling marquee using the optional LX USB programmer accessory.

  • Switchable single day programmable or non-programmable
  • Up to 2 stages of heating, 1 stage of cooling
  • Backlit display
  • Adjustable backlight intensity
  • Customizable scrolling marquee
  • Customizable service alerts and error messages
  • Switchable manual and auto changeover
  • Morning, day, evening, and night time periods
  • Outdoor sensor ready
  • Programmer compatible
  • Wireless accessories
  • Service filter reminder
  • UV lamp replacement reminder
  • Aux heat indicator
  • Random start
  • Dual units (F or C)
  • Heat pump compatible
  • Backlit, color-coded keys and legends
  • Large, easy to read backlit display
  • Configurable programmable or non-programmable
  • Configurable manual or auto changeover
  • LED indicator glows green or red to indicate cooling or heating
  • Service filter and UV light indicators
  • Non-volatile memory
  • Keypad lock
  • Dry contact input for condensate overflow