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Honeywell Home

New! Honeywell Home Programmable Thermostat, Single-Stage, 1 Heat/1 Cool Compatibility, Flexible Schedule, X2P, White, RTH21B

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Availability: In Stock.
Fulfilled by DirectSupplyClub
Arrives Friday, Jun 5
Order within 7 hours and 52 minutes
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Features

  • CUSTOMIZE: Choose to receive change air filter reminders, change out the decorative accent color with interchangeable white and gray accent pieces, and select display settings to optimize this thermostat for home. The RTH21B is a directly replacement the RTH2510, and replacement for the RTH2410 offering personalized programming of 7-day, 5-1-1 day, 5-2 day or 1 week schedule options
  • SCHEDULE: Personalize programming in 7 day, 5-1-1 day, 5-2 day or 1 week options - there's even a non-programmable option
  • EXPERIENCE: A large screen and clear font enhance daily use
  • INSTALLATION: The Honeywell Home UWP wall plate provides an easy install process and simplifies future device upgrades
  • FEATURES: Flexible scheduling, backlit display, custom display settings, change filter reminder, extended 32F low-heat setpoint, 1-year warranty
  • COMPABILITY: 1 Heat/1 Cool, 750 mV, hot water heat, forced air (gas, oil, or electric) [does not work with electric baseboard heat (120-240V)]
  • POWER: 2 AA batteries (not included)

Description

The Honeywell Home X2P Programmable Thermostat is optimized for single-stage 1 heat/1 cool systems. Its flexible scheduling technology allows personalized programming to fit your lifestyle in 5-1-1 day, 5-2 day, 7 day, or 1 week - there's even a non-programmable option. It’s a quality thermostat for your home that can be customized to receive change air filter reminders, coordinate with home decor thanks to the interchangeable decorative accent pieces (comes with white and gray options), and select display settings.

Brand: Honeywell Home


Model Name: RTH21B


Controller Type: Push Button


Special Feature: Programmable, Flexible Scheduling, Change Filter Reminder


Color: White


Controller Type: Push Button


Additional Features: Programmable, Flexible Scheduling, Change Filter Reminder


Specific Uses For Product: Home Heating and Cooling Control


Temperature Control Type: Programmable


Power Source: Battery Powered


Display Type: LCD


Control Method: Touch


Mounting Type: Wall Mount


Smart Home Compatibility: Smart Home Compatible


Color: White


Product Style: Single-Stage Compatible


Item Weight: 13.12 ounces


Brand Name: Honeywell Home


Model Name: RTH21B


Included Components: Wall Plate, Temperature Sensor


Model Number: RTH21B


UPC: 194159017368


Global Trade Identification Number: 66


Manufacturer: Resideo


Manufacturer Part Number: RTH21B


Item Type Name: Thermostat


Unit Count: 1.0 Count


Frequently asked questions

If you place your order now, the estimated arrival date for this product is: Friday, Jun 5

Yes, absolutely! You may return this product for a full refund within 30 days of receiving it.

To initiate a return, please visit our Returns Center.

View our full returns policy here.

  • Klarna Financing
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  • Afterpay Financing
  • PayTomorrow Financing
  • Financing through Apple Pay
Leasing options through Acima may also be available during checkout.

Learn more about financing & leasing here.

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Top Amazon Reviews

    • Great thermostat with a lot of options
Review Image by Elliot G.
Review Image by Elliot G.
Great thermostat!!! Lots of options and easy to install. Great value!! Love that there was a switch to have one red wire or two. Most thermostats have you cut the jumper if you wanted two or add a jumper. Lots of options. Wanted to program a single week, not 5-2 or 5-1-1. Easy to read screen and very accurate. Two things I wish it had. 1) bluetooth so you could change/program it from your phone 2) an external sensor to place somewhere else ... show more
Reviewed in the United States on January 21, 2026 by Elliot G.
    • Good product
Easy to install, works as expected.
Reviewed in the United States on March 28, 2026 by Kay
    • Good Thermostat
So far, so good. Easy to install and program. Great instructions for both the installation and programming. It does everything I need it to do. It appears to be of good quality, which is something I would expect from the Honeywell name, but only time will tell.
Reviewed in the United States on November 17, 2025 by Fred G.
    • The RTH21B Does More
Although I just installed this theermostat, I've noticed it handles more functions than listed. (1) System Changeover: the thermostat automatically switches between heating and cooling to maintain the desired temperature. (2) Smart Response: heating or cooling equipment will turn on earlier to ensure the temperature will match the setpoint at the scheduled time. (3) Tempoary and permanent schedule override. (4) Built -in compressor Protection. I must say the manual was easy to understand and quite detailed. However, I did have a question which Honeywell answered immediately. My biggest problem was the thermostat I was replacing was connected to a junction box so there was no wall on which to mount the UWP wall plate. I called Honeywell again and they had no solution. I then turned to Amazon and found a large cover plate and electrical box adapter (ARYEIELLSOW THP2400) which solved the problem perfectly. ... show more
Reviewed in the United States on April 15, 2026 by Wanster
    • Great 7-day programmable thermostat that doesn't require C-wire
Setup and programming is fairly straightforward, although you will have to use the manual during initial setup since it uses a numbering system for the menu options such as setting up conventional vs heat pump, gas vs electric, etc. It's well priced for the functionality, and I'd recommend this to anyone wanting a 7-day programmable, non-wifi thermostat, especially for those who don't have a C-wire (works with or without a C-wire). Feature highlights: Oddly, even if your system has a C-wire, it still requires 2xAA batteries for power Does not require a-C wire to function (I've tested and verified on systems with and without C-wires) Easy to mount Fan: On / Auto / Circulate Modes: Cool / Heat / Auto (auto must be enabled in setup menu) Has 4 settings per day: Wake / Home / Sleep / Away Can be used in manual mode and/or programmed with 7-day or 5/2 HVAC filter replacement reminder with lots of options such as time-running or time-period (ex: 30 days of runtime, or 30 days, etc) ... show more
Reviewed in the United States on July 17, 2025 by Tex
    • Don’t buy used.
The thermostat works well, but I bought the “used-like new” in original packaging, and it was missing the wall anchors and batteries. By the time I bought batteries, I had spent more than if I had just bought new. This was the second one I bought, the first was missing the wall plate, batteries, and actually had a different thermostat in the box than what was on the packaging. ... show more
Reviewed in the United States on March 30, 2026 by justagirl
    • Honeywell Great Thermostat
The Honeywell home thermostat is just what I was looking for to replace my old thermostat.I looked high and low, but finally found on Amazon. it’s made well, easy to install and gives me even heat through out my house. The price was pretty reasonable too. Once again Thank You Amazon for always carrying items that you can never find in nearby stores. ... show more
Reviewed in the United States on March 12, 2026 by Sallypecoraro
    • Great Unit
Easy to install and easy to program. Works well
Reviewed in the United States on December 8, 2025 by SP

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