Air
YTHX9421R5101WW Basic Prestige Kit plus wireless outdoor sensor
SKU: YTHX9421R5101WW/U
Best Seller
YTHX9421R5101WW Basic Prestige Kit plus wireless outdoor sensor
SKU: YTHX9421R5101WW/U
One Thermostat. Advanced Whole-Home Comfort
You're in control with the Honeywell Home Prestige® IAQ 2.0 Thermostat. This ENERGY STAR® certified smart thermostat and Basic Prestige Kit lets you control your entire home's comfort via temperature, humidification, air-conditioning and ventilation. In addition, RedLINK® Technology lets you adjust these settings remotely.

Product Overview
The Prestige® IAQ Thermostat with RedLINK® features an effortless, 7-day programmable color touchscreen that provides control of temperature, dehumidification and ventilation. Its high-definition, full-color display is easy to read. The ENERGY STAR® certified smart thermostat interviews you and uses your answers to program itself.
No need to work through complicated settings and instructions. Optional add-ons include the Portable Comfort Control that allows you to adjust room temperatures from anywhere in the home.
Features
YTHX9421R5101WW Basic Prestige Kit plus wireless outdoor sensor
Adapts to Your Routine
Designed with a color touchscreen display, using the Prestige® thermostat is simple and intuitive. View the current temperature and humidity, make adjustments, program a heating and cooling schedule for every day of the week, or locate your installer's contact information for service.
Adaptive Intelligent Recovery
Over time, the Prestige® thermostat learns how long it takes your system to reach the ideal temperature you want. It activates the heating or cooling system earlier and helps make sure you're comfortable at the time you expect.
Expand Your System for Maximum Performance
Get the most from your Prestige® IAQ Kit with RedLINK®, EIM and Wireless Outdoor Sensors with compatible accessories. The Equipment Interface Module, duct and outdoor sensors expand the system's range for more data and visibility. Use RedLINK® to connect the thermostat to the internet for mobile alerts and control.
Works with
Our products, apps and services work in harmony with leading smart home ecosystems.
Thermostat Type | Programmable, Digital, Low Voltage, RedLINK |
---|---|
RedLINK | Yes |
Color | Front: White, Side: White |
Includes | THX9421R5021WW Prestige® 2-Wire IAQ Thermostat, THM5421R1021 Equipment Interface Module, C7089R1013 Wireless Outdoor Sensor, 2 Duct Sensors |
Utility Rewards | No |
Stages | Up to 4 Heat/2 Cool Heat Pump Systems, Up to 3 Heat/2 Cool Conventional Systems |
Modes of Operation | Heating, Cooling |
Program Type | 7-Day Programmable, Manual / Not Programmed |
Fan Function | On, Auto, Circulating |
Display Type | Touch Screen |
Is Your Home Compatible?
Knowing your home's wiring can make a difference. Follow these step-by-step instructions to identify if your current wiring is compatible with this thermostat.

Get Started
Professional installations gets professional results. Find an authorized professional near you to complete your installation.
Resources

Take It All with You
Gain control over their connected devices from anywhere at any time through the Total Connect® Comfort App. You can monitor and adjust heating and cooling usage, stay on top of indoor humidity levels, and automatically receive email alerts related to safety, comfort and energy. The app works with a wide range of popular connected devices.