Honeywell Home RTH21B Programmable Thermostat – Single-Stage, Flexible Schedule, White

Upgrade your comfort with Honeywell Home X2P Programmable Thermostat

The Honeywell Home RTH21B is built for single-stage systems and provides dependable control for 1 heat/1 cool setups. The large backlit display and clear typography make it easy to read temperatures at a glance, from hallway to bedroom. As a modern update to earlier models, it blends straightforward daily use with flexible programming that can adapt to your routine.

Flexible scheduling that fits your week

Choose among several programming patterns to save time and energy:

• 7 day schedule
• 5-1-1 day pattern
• 5-2 day pattern
• 1 week schedule
• Non-programmable option

Each option supports on-demand adjustments, so you can tweak temperature changes for mornings, evenings, or days when plans shift.

Decor and display options

• Interchangeable white and gray accent pieces to coordinate with your decor
• Display customization settings to suit lighting in your space
• Change air filter reminders to help maintain equipment and efficiency

The RTH21B includes a user-friendly UWP wall plate for a smoother installation path and easier future upgrades. With a large, backlit screen and a comfortable interface, daily use feels intuitive even after a busy day. A lower heat point at 32°F supports a wider range of heating systems, while a reliable 1-year warranty helps cover typical wear and tear.

Power, compatibility, and durability

• Power: two AA batteries (not included)
• Compatibility: 1 Heat/1 Cool, hot water heat, and forced air systems (gas, oil, or electric); not compatible with electric baseboard heat (120-240V)
• Durability: designed for long-term performance in living spaces

In practice, homeowners discover this model’s balance of simplicity and flexibility. You can set a weekday rhythm that mirrors your work schedule, then switch to a weekend pattern without reprogramming from scratch. It’s a practical option for those who want reliable automation without steep learning curves.