Prestige HD 7-Day Programmable Thermostat

Get the App Here:

Get it on Google Play

Take comfort in what you see

See and experience the difference with our Prestige® HD 7-Day Programmable Thermostat. With a display that’s in full color and in high-definition, it is easy to read and understand, even across the room. You will also find it’s simple and intuitive to enter information. The system interviews you and uses your answers to program itself. And with Portable Comfort Control, you’ll be able to adjust the temperature with a remote you can take anywhere in the house. No late-night visits to the thermostat, just use your mobile device.

  • Seven-day programming
  • Simple touch-screen technology
  • Displays outdoor temperature and humidity (with Wireless Outdoor Air Sensor)
  • ENERGY STAR® certified
  • Trilingual (displays in English, Spanish or French)
  • Five-year warranty
  • Professional installation
High-Definition, Full-Color Display
It’s visually stunning and easy to read. Optional: SD — Standard Definition (black/white).
Interview-Based Programming
The system interviews you and uses your answers to program itself. No need to work through complicated settings and instructions.
Temperature Control on Demand
Check/change temperature from anywhere in the home (with Portable Comfort Control)
All-in-One Control
Control temperature and indoor air quality from one convenient control
Model/Sku #
Model numbers: THX9421R5021WW, YTHX9421R5085WW, YTHX9421R5101WW, YTHX9421R5127WW

Prestige? HD 7-Day Programmable Thermostat

Prestige Thermostat
Honeywell Redesigned Prestige IAQ


No. Only one Portable Comfort Control can be connected to one thermostat.
Yes, the Prestige thermostat allows the owner to lock the screen with a password. To set a password on the thermostat: Press the menu tab. Scroll down to and select Security Settings. Press Create Password and note the four digit code provided. Write the password in the space provided in the owner's manual or another safe location. Press Done to exit. Press Change Lock Mode Select the level of protection desired. Press Done. Press the Previous Menu tab to return to the Menu screen.
Press "Menu: followed by "Equipment Status". This shows the status of the heating and the cooling equipment and the number of stages engaged.
The Portable Comfort Control allows you to control the system status (i.e. heat off or cool and the temperature settings for thermostat). If only one thermostat is connected, then you can control the temperature from the location of the handheld or the thermostat. If more than one thermostat is connected, then you can toggle between different zones of the house.
One Portable Comfort Control can manage up to 16 thermostats. I am unsure of the voltage coming up to my thermostat. How do I find out? Answer: Honeywell offers thermostats for both low voltage (24 volts) and line voltage (120 or 240 volts) systems. The most common type of voltage from a central heating and/or cooling system is 24 volts (24Vac). The old thermostat may say somewhere on the thermostat that it is for 24 volt (24Vac) or maximum 30 volts (30Vac). If you see 120 Vac or 240 Vac on the thermostat, a low voltage thermostat will NOT work with your system. You will need a line voltage thermostat. This type of voltage is common with electric baseboard heating. Regardless of the voltage, Honeywell strongly suggests that you turn off the power to the system at the furnace, at the fuse, or at the circuit breaker panel before installing or replacing a thermostat. If you are unsure about your voltage, please contact a local heating and cooling contractor in your area for assistance.
Yes, the packaging contained with the thermostat is recyclable. Information about recycling thermostats containing mercury can be found at:
The FAN selection key has two or three positions: Auto and On and sometimes Circ (Circulate). The Auto position will allow the system fan to operate whenever the heating or cooling system is turned on by the thermostat. The On position will turn the fan on to run continuously, regardless whether heating or cooling system is turned on by the thermostat or not. The Circ (Circulate) position if available will run the fan approximately 35% of the time, minus any time the fan will run with the heating or cooling system.
Yes. When connected with an Outdoor Sensor, select thermostats and devices will display the outdoor temperature and humidity on the screen
Your thermostat is designed to control temperature to +/- 1 F. How often your heat turns on and off depends on several factors including the type of heating system you have and load conditions (in other words, how hot or cold it is outside). A typical mid-efficiency forced air system will cycle about five times in an hour (5CPH) under typical load conditions. A typical high efficiency furnace or hot water system would cycle less than that. The installer can adjust the cycle rate setting on the thermostat.
If the VisionPRO Thermostat does not allow you to change the humidity settings, then it is not setup for dehumidification or humidification control. In this case Honeywell recommends speaking to the installing contractor of the thermostat.

If we weren't able to answer your question please visit Help & Support


Download PDF
Prestige® HD 7-Day Programmable Thermostat Operating Manual
Model: THX9321, THX 9421
Download PDF
Prestige® HD 7-Day Programmable Thermostat Operating Manual
Model: THX9321, THX 9421
Download PDF
Prestige® HD 7-Day Programmable Thermostat Operating Manual
Model: THX9000

Need support for this product?