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Conserve Energy by Running Your Thermostat Only at Pre-Set Times
Honeywell RTH221B1021/A 1-Week Programmable Thermostat
Honeywell RTH221B1021/A 1-Week Programmable Thermostat
Honeywell RTH221B1021/A 1-Week Programmable Thermostat
Item# 20498
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  • Basic operation with precise temperature control
  • Simple Programming
  • Energy Savings
  • Sleek one-piece design
  • Works with heating and cooling systems

Essential Info

The Honeywell RTH221B1021/A 5-1-1 Day Programmable Thermostat is designed to provide you with push-button climate control, with advanced programming schedules to save energy, while offering the reliability to give you many years of service. In contrast to Non-Programmable thermostats which simply allow you to select a setpoint temperature and turn the thermostat to cool or heat, a Programmable thermostat allows you to create schedules for automatically running your cooling or heating system a certain times. A 1-Week Programmable Thermostat is best if you tend to keep one schedule for the entire week. The thermostat is pre-programmed with a set schedule; however this is easily modified to fit your lifestyle, as you can create one program for the entire week with 4 periods per day. You can even temporarily ignore the programmed schedule by using the up or down arrow buttons to adjust the temperature. There is a battery backup, two AAA batteries required (sold separately), that will maintain your setpoint even if you lose power; a low battery indicator displays when the batteries need to be replaced. A built-in compressor protection feature helps prevent damage to the compressor in your air conditioning or heat pump system which can occur if the compressor is restarted too soon after shutdown.

This thermostat is compatible with the following systems:
• Gas, oil or electric furnace
• Central air conditioner
• Hot water system with or without pump
• Millivolt system
• Central heating and cooling system
• Heat pump without auxiliary/backup heat

Please Note: This thermostat does not work with heat pump systems and electric baseboard heat (120v-240V)


What's Included

  • 1x - Thermostat
  • 1x - Wall Plate
  • 1x - Set of Mounting Hardware
  • 1x - Set of Wire labels
  • 1x - Quick-Start Guide
  • 1x - Owner's Manual
  • More Info

     Pre-Programmed Factory Schedule Settings
     Period  Start Time HeatCool
    Wake6:00am70° F (21° C)75° F (24° C)
    Leave8:00am 62° F (16.5° C)  83° F (28.5° C) 
    Return6:00pm70° F (21° C)75° F (24° C)
    Sleep10:00pm62° F (16.5° C)78° F (25.5° C)

    These settings can be modified at any time to fit with your schedule. It’s easy to program your system for maximum energy savings. You can program four time periods each day, with different settings for weekdays and weekends.
    WAKE - the time you awaken and the temperature you want in the morning, until you leave for the day
    LEAVE - the time you leave home and the temperature you want while you are away (energy-saving level)
    RETURN - the time you return home and the temperature you want during the evening, until bedtime
    SLEEP - the time you go to bed and the temperature you want overnight (energy-saving level)


    Manufacturer Product No.RTH221B1021/A
    Heating Range40° F to 90° F (4.5° C to 32° C)
    Cooling Range50° F to 99° F (10° C to 37° C)
    Operating Ambient Temperature32° F to 122° F (0° C to 50° C)
    Operating Relative Humidity5% to 90% (non-condensing)
    Backup Power2x AAA batteries
    Manufacturer Warranty1-year limited



    Sony Alkaline AAA batteries       
    Sony Alkaline AAA batteries       

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