Honeywell Home THX900W1 Smart Wifi Thermostat 3H/2C

Product Description

The HONEYWELL HOME THX900W1 is a hardwired, C-wire-required smart WiFi thermostat designed for residential and light commercial HVAC applications. It supports up to 3H/2C heat pump staging or 2H/2C conventional staging across gas, oil, electric warm air, hydronic, fan coil, and PTAC systems. The 4.3 sq. in. touchscreen displays in English, French, or Spanish and supports heat, cool, auto, off, and emergency heat operating modes. Built-in humidity sensing with a 5 to 90 percent RH operating range and a configurable control output allow technicians to manage IAQ equipment or add an additional heating or cooling stage on a single device.

This thermostat is suited for both residential and light commercial installs where multi-stage control, smart connectivity, and remote management are required. It mounts to a standard J-box in a horizontal wall orientation using the UWP wall plate, making retrofits and upgrades straightforward. Auto or manual heat-cool changeover and time-based or Smart Away programming provide scheduling flexibility across a wide range of job types. Rated for ambient operating temperatures of 37 degrees F to 102 degrees F, this unit covers a broad range of installation environments. It is supported by Pro-IQ services through the Resideo Pro app for remote setup, saved install templates, and system alerts.

Key Features

• Supports up to 3H/2C heat pump or 2H/2C conventional multi-stage systems including gas, oil, electric warm air, hydronic, fan coil, and PTAC
• 4.3 sq. in. customizable touchscreen with selectable English, French, or Spanish display
• Built-in humidity sensing across 5 to 90 percent RH operating range with configurable IAQ or extra-stage control output
• WiFi-enabled and Matter-compatible; works with Google Home, Amazon Alexa, and Apple Home
• Mounts to standard J-box with UWP wall plate for fast retrofits and upgrades
• ENERGY STAR certified and eligible for utility rebates; backed by a 5-year warranty
• Pro-IQ support via Resideo Pro app for remote configuration, saved templates, and system alerts

Compatibility

Designed as a drop-in upgrade replacement for the TH6320WF2003/U and TH6220WF2006/U. Compatible with 24 Vac gas, oil, electric warm air, hydronic, fan coil, and PTAC systems requiring up to 3H/2C heat pump or 2H/2C conventional staging. C-wire is required.

Installation Notes

Installation should be performed by a licensed HVAC technician familiar with low-voltage thermostat wiring and local mechanical codes. Power down the system at the air handler or furnace disconnect and confirm zero voltage at the thermostat base before wiring. A dedicated C-wire is required for operation; do not attempt to power the unit through add-a-wire adapters unless confirmed compatible. Follow the Resideo Pro app setup flow to complete commissioning and register the unit for warranty and Pro-IQ service access.