---
product_id: 27042208
title: "RTH221B1039 RTH221B Programmable Thermostat, White"
brand: "honeywell home"
price: "€ 63.49"
currency: EUR
in_stock: true
reviews_count: 8
url: https://www.desertcart.gr/products/27042208-rth221b1039-rth221b-programmable-thermostat-white
store_origin: GR
region: Greece
---

# 1-week programmable schedule low battery reminder ±1°F precise temp control RTH221B1039 RTH221B Programmable Thermostat, White

**Brand:** honeywell home
**Price:** € 63.49
**Availability:** ✅ In Stock

## Summary

> 🌡️ Stay ahead of the chill—comfort that programs itself!

## Quick Answers

- **What is this?** RTH221B1039 RTH221B Programmable Thermostat, White by honeywell home
- **How much does it cost?** € 63.49 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.gr](https://www.desertcart.gr/products/27042208-rth221b1039-rth221b-programmable-thermostat-white)

## Best For

- honeywell home enthusiasts

## Why This Product

- Trusted honeywell home brand quality
- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Key Features

- • **Smart Power Backup:** Never lose your settings during outages—your thermostat remembers your preferences so you stay cozy without interruption.
- • **DIY-Friendly Installation:** Get up and running fast with straightforward, step-by-step instructions—no professional needed, just your savvy hands and a mini screwdriver.
- • **Intuitive Digital Interface:** Navigate easily with a crisp, no-fuss digital display offering Fahrenheit/Celsius and 12/24-hour clock options, designed for quick one-touch adjustments.
- • **Effortless Weekly Scheduling:** Set one simple program for all 7 days with 4 customizable periods—wake, leave, return, sleep—so your home’s comfort adapts seamlessly to your lifestyle.
- • **Precision Temperature Mastery:** Maintain your ideal climate with ±1°F accuracy, ensuring energy-efficient comfort without the guesswork or temperature swings.

## Overview

The Honeywell Home RTH221B1039 is a sleek, white programmable thermostat designed for simple, energy-saving temperature control. Featuring one-week programming with four daily periods, ±1°F precision, and easy DIY installation, it offers reliable comfort management for heating and cooling systems without auxiliary heat. Its digital display supports Fahrenheit or Celsius and 12/24-hour clocks, with built-in low battery reminders and memory retention during power outages, making it a smart, budget-friendly upgrade for modern homes.

## Description

Product Description This easy-to-operate 1-Week Programmable Thermostat helps make your home comfortable exactly when you want it. Programmable for one week, it lets you customize your schedule with four options – ‘wake’, ‘leave’, ‘return’, and ‘sleep’ – for precise temperature control and added comfort. Simple step-by-step instructions included with the thermostat make DIY installation easy. From the Manufacturer A Honeywell programmable thermostat can save you significant money off your energy bill. You set it up to adjust the temperature when you are away or asleep---times when you don’t necessarily need to heat or cool your home to optimum comfort---and your heating and cooling equipment runs less. This one-piece thermostat has one easy program for all days of the week (4 periods - wake, leave, return, sleep). Simple and effective use and performance.

Review: Excellent Basic Programmable Thermostat - I can't believe I waited so long to replace the old mercury bubble thermostat on my hot water heat system. I noticed a friend had a new one, so I decided it was time to do some research here at desertcart. I wanted a vertical style to match the placement of the old one which narrowed the field considerably. I wanted a simple day/night setback and didn't need separate settings for weekends. I wanted simple controls and ease of temporary adjustment. This one fit the bill perfectly. Installation was a breeze. The instructions are clear and easy to follow. My two-wire system connected to the Rh (Red - heat) and W (White) terminals. The wires weren't that color (probably the original 90 year old wires!) so I either guessed right or, more likely, it would have worked if they were reversed since it's simply an open/close switch to activate the heater. I even reused the mounting screws from the old unit - sweet! Stop by your local Dollar Store and pick up a mini screwdriver set if you don't have one. Programming is straightforward, and again the instructions are clear. It comes preprogrammed with four periods - Wake, Leave, Return, and Sleep. It's easy to adjust these to your desired time/temp. I skipped two of them completely by simply pressing the Hold button for four seconds while that period was displayed during setup. Believe me, you'll be tweaking your settings with abandon after the first run-through... it's that easy. I love the simplicity of the display. What's the current temp? Look at the screen. You're a bit cold? Tap the up arrow once and read the setpoint; tap it again to temporarily raise the setpoint one degree, again for two degrees, etc. The unit will retain your temporary setting until the next programed change (e.g. night setback) or until you press the Run button. Going away for a couple of days? Tap in the desired setpoint and press Hold. Simply press Run again when you get home. As noted in other reviews, there is no backlight in the display. You can download the installation and user's manual at the Honeywell website to get a peek at how it works. Be sure to note the Configuration Menu in the installation instructions. I had to change the "Heating Cycles per Hour" setting to "3" (for my hot water system) from the default "5" setting. What is Heating Cycles per Hour, you ask? It's a means to fine-tune the efficiency of the system's attempts to maintain your desired temperature. It's ONLY active when you're within a degree or so of the setpoint temperature. Here's how it works: Say, your setpoint temperature is 70°. As the heater brings the room air temp up towards the setpoint, an anticipator circuit cuts off the heat at a predetermined value, say 69° to keep from overshooting your requested 70°. Ideally, the residual heat from your burner/blower/fan/radiator will gently nudge the air temp up to 70°, and all is right with the world. So far we have: temp below 69°, run heater; temp above 70°, stop heater. But what happens between 69° and 70°? What if there wasn't enough residual heat to get to 70°? Or what if your furnace isn't sized properly, or your insulation is weak, or the kids left a window open? Where's that 70° you requested? This is where you heater starts cycling. My "Cycles per Hour" is set to 3, which means 3 twenty minute cycles each hour consisting of 10 minutes OFF, 10 minutes ON. When the air temp hit 69° the heater stopped for 10 minutes, hoping the air temp will reach the magic 70°. 10 minutes later it takes a peek at the temp... 70° or above? Great! Job done. No cycling involved. Oops - only 69.3°? - start up again for 10 minutes, shut down, wait 10 minutes and check again. 69.8° this time? Start up again for 10 minutes and another cycle. This time, let's say the temp hit 70° after 8 minutes of heat. Great! - job done, shut off heat and stop cycling. It might overshoot to about 70.3° this time - well within your comfort zone. Now, sit warm and cozy in front of the TV as the temp slowly falls from 70.3° to 69° and listen for the cycling to begin again. If you're well insulated, it's a fairly mild night, and your heater is sized properly, it might go through a cycle every couple of hours. If there's a blizzard blowing outside your poorly insulated shack, it might cycle on and off every 10 minutes, or even stay on constantly if it can't get you above 69°. To recap: Temp below setpoint minus one: heater ON. Temp above setpoint: heater OFF. In between: cycle ON and OFF in attempt to efficiently get to setpoint without too much overshoot. Why? A heater is more efficient running longer cycles rather than rapid On/Off cycles. A heater with a lot of "thermal inertia" - like my hot water system, takes a while for those warm radiators to gently get the air temperature to the desired setpoint... it needs cycles a bit longer to be efficient and effective. A rapid heat system, like an electric wall heater, will get that air temp up quickly - it needs a higher cycle rate / shorter 'burn' time to stay efficient and avoid overshoots. In fact, the cycle rate for electric heat is 9: that's 9 cycles of 6.7 minutes per hour. Air conditioning cycle/hour is fixed at 3. One more thing: if you want the fancier model, the Honeywell TH2110D1009 is the same unit, but with backlight, 5/2 day programming, and something called "Adaptive Intelligent Recovery" which learns how fast your heater gets you to your desired temperature so that you can program it to BE at a given temperature at a given time... handy for those early morning middle-of-winter wake ups! Be sure to properly dispose of that mercury! Enjoy!
Review: A great value for your buck! - Super easy to self install! Very durable and easy to program and use! Very good replacement thermostat option! It is programmable, it doesn’t have a back light on it but are able to program wake, leave, return, and sleep times/settings for both cooling and heating settings!

## Features

- ONE WEEK PROGRAMMING: Set one identical program for the entire week with four program periods per day including wake, leave, arrive and sleep.
- PRECISE TEMPERATURE CONTROL: Precise temperature control of plus/- 1 degree Fahrenheit
- DIGITAL DISPLAY: Easy-to-read digital display with an intuitive interface for one-touch access to setpoint temperature
- EASY INSTALLATION: Easy to install yourself and basic operation keeps programming simple
- REMINDERS: Built-in battery change reminders (2 AAA batteries are required for operation)
- SET POINT RETENTION: Set point is retained in memory in the event of a power outage
- DISPLAY OPTIONS: Fahrenheit or Celsius; 12 or 24 hour clock. Note: This thermostat is not backlit.
- OVERRIDE OPTIONS: Permanent and temporary override capability
- COMPATIBLE WITH: Heating, cooling and heat pumps without auxiliary heat options
- Does NOT work with electric baseboard heat (120-240 V), heat pumps with backup, or multi-stage heating/cooling. For indoor use only.

## Technical Specifications

| Specification | Value |
|---------------|-------|
| ASIN | B018A3DHJY |
| Additional Features | Clock Display, Low Battery Indicator, Low Voltage, Programmable |
| Backlight | Yes |
| Best Sellers Rank | #61,244 in Tools & Home Improvement ( See Top 100 in Tools & Home Improvement ) #107 in Home Programmable Thermostats |
| Brand | Honeywell Home |
| Brand Name | Honeywell Home |
| Color | White |
| Connectivity Technology | Non-connected |
| Control Method | Touch |
| Control Type | Button Control |
| Controller Type | Hand Control |
| Customer Reviews | 4.3 out of 5 stars 7,692 Reviews |
| Display Type | Digital |
| Finish Types | White |
| Global Trade Identification Number | 00085267348553 |
| Included Components | Mounting Hardware, Thermostat, User Manual |
| Item Dimensions D x W x H | 1"D x 4.75"W x 3.5"H |
| Item Height | 3.5 inches |
| Item Type Name | Programmable Thermostat |
| Manufacturer | Honeywell |
| Manufacturer Warranty Description | 1 year limited. |
| Material Type | Plastic |
| Model Name | RTH221B |
| Model Number | RTH221B1039 |
| Mounting Type | Wall Mount |
| Number of Batteries | 2 AA batteries required. |
| Power Source | Battery Powered |
| Product Dimensions | 1"D x 4.75"W x 3.5"H |
| Product Style | Contemporary |
| Shape | Curved |
| Special Feature | Clock Display, Low Battery Indicator, Low Voltage, Programmable |
| Specific Uses For Product | Air Conditioner, Furnace |
| Specification Met | energy |
| Temperature Control Type | Heating and Cooling |
| UPC | 085267348553 |
| Voltage | 24 Volts |

## Product Details

- **Brand:** Honeywell Home
- **Controller Type:** Hand Control
- **Model Name:** RTH221B
- **Product Dimensions:** 1"D x 4.75"W x 3.5"H
- **Special Feature:** Clock Display, Low Battery Indicator, Low Voltage, Programmable

## Images

![RTH221B1039 RTH221B Programmable Thermostat, White - Image 1](https://m.media-amazon.com/images/I/51lBvaXOEpL.jpg)
![RTH221B1039 RTH221B Programmable Thermostat, White - Image 2](https://m.media-amazon.com/images/I/61EWhMzTYQL.jpg)
![RTH221B1039 RTH221B Programmable Thermostat, White - Image 3](https://m.media-amazon.com/images/I/61czZlHOxkL.jpg)
![RTH221B1039 RTH221B Programmable Thermostat, White - Image 4](https://m.media-amazon.com/images/I/61iKrtr0k1L.jpg)
![RTH221B1039 RTH221B Programmable Thermostat, White - Image 5](https://m.media-amazon.com/images/I/61vHS9CYO7S.jpg)

## Available Options

This product comes in different **Size, Style** options.

## Questions & Answers

**Q: How did everyone else get the red wire in if it is so tightly screwed in? I can’t seem to get it to budge, even with the correct size screwdriver.**
A: I used a small flathead that fit in the slot. Then used pliers on the shaft of the screwdriver. I used the pliers to turn the screwdriver and I was able to loosen the screw

**Q: Where can I find an owners manual?**
A: Jeezus people, if the person is asking isn’t it obvious he does not have it in the box?!! The least helpful answers ever. I inherited the thermostat from a previous owner and in search for a manual, too. Guess what— no box!!

**Q: How do I put it on. I cannot program it**
A: Hi, thank you for reaching out with this. We would like to gather some more information on your specific system so that we can provide assistance on how to program. Please reach out to our support team on Facebook/Twitter with a private message. We look forward to hearing from you soon. -Jim

**Q: does this thermostat use a battery for power? and how long should the battery last if it needs one**
A: Hi there, this thermostat requires 2 AAA batteries, battery life depends on the usage, we recommend replacing batteries at least every year. - Maria

## Customer Reviews

### ⭐⭐⭐⭐⭐ Excellent Basic Programmable Thermostat
*by I***E on March 1, 2010*

I can't believe I waited so long to replace the old mercury bubble thermostat on my hot water heat system. I noticed a friend had a new one, so I decided it was time to do some research here at Amazon. I wanted a vertical style to match the placement of the old one which narrowed the field considerably. I wanted a simple day/night setback and didn't need separate settings for weekends. I wanted simple controls and ease of temporary adjustment. This one fit the bill perfectly. Installation was a breeze. The instructions are clear and easy to follow. My two-wire system connected to the Rh (Red - heat) and W (White) terminals. The wires weren't that color (probably the original 90 year old wires!) so I either guessed right or, more likely, it would have worked if they were reversed since it's simply an open/close switch to activate the heater. I even reused the mounting screws from the old unit - sweet! Stop by your local Dollar Store and pick up a mini screwdriver set if you don't have one. Programming is straightforward, and again the instructions are clear. It comes preprogrammed with four periods - Wake, Leave, Return, and Sleep. It's easy to adjust these to your desired time/temp. I skipped two of them completely by simply pressing the Hold button for four seconds while that period was displayed during setup. Believe me, you'll be tweaking your settings with abandon after the first run-through... it's that easy. I love the simplicity of the display. What's the current temp? Look at the screen. You're a bit cold? Tap the up arrow once and read the setpoint; tap it again to temporarily raise the setpoint one degree, again for two degrees, etc. The unit will retain your temporary setting until the next programed change (e.g. night setback) or until you press the Run button. Going away for a couple of days? Tap in the desired setpoint and press Hold. Simply press Run again when you get home. As noted in other reviews, there is no backlight in the display. You can download the installation and user's manual at the Honeywell website to get a peek at how it works. Be sure to note the Configuration Menu in the installation instructions. I had to change the "Heating Cycles per Hour" setting to "3" (for my hot water system) from the default "5" setting. What is Heating Cycles per Hour, you ask? It's a means to fine-tune the efficiency of the system's attempts to maintain your desired temperature. It's ONLY active when you're within a degree or so of the setpoint temperature. Here's how it works: Say, your setpoint temperature is 70°. As the heater brings the room air temp up towards the setpoint, an anticipator circuit cuts off the heat at a predetermined value, say 69° to keep from overshooting your requested 70°. Ideally, the residual heat from your burner/blower/fan/radiator will gently nudge the air temp up to 70°, and all is right with the world. So far we have: temp below 69°, run heater; temp above 70°, stop heater. But what happens between 69° and 70°? What if there wasn't enough residual heat to get to 70°? Or what if your furnace isn't sized properly, or your insulation is weak, or the kids left a window open? Where's that 70° you requested? This is where you heater starts cycling. My "Cycles per Hour" is set to 3, which means 3 twenty minute cycles each hour consisting of 10 minutes OFF, 10 minutes ON. When the air temp hit 69° the heater stopped for 10 minutes, hoping the air temp will reach the magic 70°. 10 minutes later it takes a peek at the temp... 70° or above? Great! Job done. No cycling involved. Oops - only 69.3°? - start up again for 10 minutes, shut down, wait 10 minutes and check again. 69.8° this time? Start up again for 10 minutes and another cycle. This time, let's say the temp hit 70° after 8 minutes of heat. Great! - job done, shut off heat and stop cycling. It might overshoot to about 70.3° this time - well within your comfort zone. Now, sit warm and cozy in front of the TV as the temp slowly falls from 70.3° to 69° and listen for the cycling to begin again. If you're well insulated, it's a fairly mild night, and your heater is sized properly, it might go through a cycle every couple of hours. If there's a blizzard blowing outside your poorly insulated shack, it might cycle on and off every 10 minutes, or even stay on constantly if it can't get you above 69°. To recap: Temp below setpoint minus one: heater ON. Temp above setpoint: heater OFF. In between: cycle ON and OFF in attempt to efficiently get to setpoint without too much overshoot. Why? A heater is more efficient running longer cycles rather than rapid On/Off cycles. A heater with a lot of "thermal inertia" - like my hot water system, takes a while for those warm radiators to gently get the air temperature to the desired setpoint... it needs cycles a bit longer to be efficient and effective. A rapid heat system, like an electric wall heater, will get that air temp up quickly - it needs a higher cycle rate / shorter 'burn' time to stay efficient and avoid overshoots. In fact, the cycle rate for electric heat is 9: that's 9 cycles of 6.7 minutes per hour. Air conditioning cycle/hour is fixed at 3. One more thing: if you want the fancier model, the Honeywell TH2110D1009 is the same unit, but with backlight, 5/2 day programming, and something called "Adaptive Intelligent Recovery" which learns how fast your heater gets you to your desired temperature so that you can program it to BE at a given temperature at a given time... handy for those early morning middle-of-winter wake ups! Be sure to properly dispose of that mercury! Enjoy!

### ⭐⭐⭐⭐⭐ A great value for your buck!
*by I***A on November 3, 2025*

Super easy to self install! Very durable and easy to program and use! Very good replacement thermostat option! It is programmable, it doesn’t have a back light on it but are able to program wake, leave, return, and sleep times/settings for both cooling and heating settings!

### ⭐⭐⭐⭐ Simple to Use and Reliable — Perfect for Basic Temperature Control
*by D***R on October 8, 2025*

This thermostat does exactly what it’s meant to, keeps your home at a comfortable temperature without any complicated setup. Installation was quick and straightforward, even for someone who’s not super handy. The instructions were clear, and it powered right up once connected. The display is easy to read, and the programmable feature is great for setting different temps during the day and night. It’s not fancy or smart-home compatible, but that’s also what I like about it, fewer buttons, fewer issues. Once set, it keeps the temperature steady and accurate, and it’s easy to adjust when needed. If you’re looking for a no-frills, dependable thermostat that just works, this one’s a solid choice. Pro tip: double-check your wiring before installing, it makes the whole process even smoother.

## Frequently Bought Together

- Honeywell Home RTH221B1039 1-Week Programmable Thermostat
- 24V 40VA Control Transformer， Primary 120, 208, 240V Secondary 24V Isolation Transformers，24V Transformer with Foot Mount for HVAC Furnace Multi Tap

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*Product available on Desertcart Greece*
*Store origin: GR*
*Last updated: 2026-02-05*