1-Week Programmable Thermostat RTH221B1021

DIY Install
This 1-Week Programmable Thermostat is simple to install, easy to use and has basic operations. Features such as precise temperature control maximize comfort.
Verify compatibility with your home heating and cooling system, remove your existing thermostat and follow step-by-step instructions for installation.

Basic operations. Simple to use.

Our 1-Week Programmable Thermostat has basic operations and is simple to use. It takes one program for the entire week, plus there are four periods per day you can program for like sleep, wake, leave and return. You can install it yourself, and it’s compatible with most heating and cooling systems.

  • Simple programming (one program for entire week, plus four periods per day)
  • Easy to use
  • Basic operation
  • 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 RTH221B1021

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 RTH221B1021

How to install and program your Honeywell thermostat