Honeywell Home YTHX9421R5127WW/U Prestige IAQ Thermostat with RedLINK, EIM and Sensors

Optimize comfort, uptime and serviceability with the Honeywell Home Prestige IAQ thermostat — a professional-grade, 2-wire programmable thermostat designed for residential and light-commercial HVAC and IAQ control. The high-definition color touch screen plus Smart Schedule lets technicians and occupants set precise 7-day schedules in seconds, while compatibility with the Equipment Interface Module (EIM) and RedLINK accessories delivers secure wireless monitoring and remote control. Support for up to 4 stages of heat and 2 stages of cool (heat pump systems) and multiple IAQ contacts enables integrated humidification, dehumidification and ventilation control to protect equipment and occupant health. Built-in Delta T alerts, performance logs and a searchable alerts history speed diagnostics and reduce truck rolls — valuable for service contractors and facility managers. Title 24 compliant and Energy Star qualified, the Prestige IAQ also supports USB setup transfer and dealer branding for faster installs and consistent configurations across sites. Ideal for HVAC, building management and security-conscious installations that require environmental monitoring alongside surveillance or access control systems. Contact your dealer or add to cart to upgrade building comfort and operational visibility.

• Simplify installation and wiring: 2-wire thermostat with Equipment Interface Module (EIM) moves HVAC and IAQ wiring away from the control point, reducing install time and callbacks.
• Reliable multi-stage control: Manages up to 4 heat / 2 cool stages in heat pump systems for precise comfort in residential and light-commercial sites.
• Proactive system monitoring: Delta T alerts, performance logs and diagnostics speed troubleshooting and protect equipment — ideal for building managers and service contractors.
• Expandable RedLINK ecosystem: Wireless RedLINK accessories and Internet Gateway enable remote monitoring, scheduling and integration with building networks.
• Installer-friendly features: Smart Schedule programming, USB setup transfer, customizable service reminders and tri-lingual display reduce service visits and improve customer retention.