1-Week Programmable Thermostat RTH221B

DIY Install
The 1-Week Programmable Thermostat offers basic operation in a sleek one-piece design. Programming it is easy and contributes to its ease of use, along with smart features such as precise temperature control.
Verify compatibility with your home heating and cooling system, remove your existing thermostat and follow step-by-step instructions for installation.
Programming simplified. Performance assured.

Our basic 1-Week Programmable Thermostat is easy to operate and has simple programming. There’s only one program for the entire week. You can select up to four options such as wake, leave, return and sleep to customize your weekly schedule. Other features such as precise temperature control add to your comfort level.

  • Simple programming (one program for entire week, plus four periods per day)
  • Easy to use
  • Precise temperature control
  • Sleek one-piece design
  • One-year warranty
  • DIY installation
  • Model number: RTH221B1021
  • Dimensions:3-3/8 in. wide x 4-3/4 in. high x 1-1/8 in. deep

1-Week Programmable Thermostat RTH221B

Honeywell explains Programmable Thermostat

Compatible with systems

  • This thermostat is compatible with heating/cooling systems.
  • It is not compatible with heat pump systems or electric baseboard heat (120/240V).

Simply choose the installation instructions option you prefer:

Video-Guided Installation

The video below shows the installation process from start to finish.

Quick Start Manuals & Guides PDF

Visit the resources section below to download PDFs of manuals and guides, such as Quick Start and User Guides.

1-Week Programmable Thermostat RTH221

How to install and program your Honeywell thermostat