How to Program a Honeywell Digital Thermostat

If you have a programmable digital thermostat, there is a very good chance it is a Honeywell model. The leading maker of thermostats, Honeywell offers dozens of different models, ranging from very simple styles that allow you set a single automated program that is the same every day, to elaborate touch-screen models that make it possible to set a different group of automatic temperature adjustments for each day of the week.

Digital thermostat
credit: Ryan McVay/Photodisc/Getty Images
Digital programmable thermostats come in many styles.

The advantage of programmable thermostats is now well known to almost everyone. By automating the process of turning down the temperature at night or when you are away from the house, you can enjoy energy savings that range from 10% to 30%.

Identifying if Your Thermostat is Programmable

While a great many (maybe most) thermostats made by Honeywell are now digital programmable models, there are still simple operational thermostats manufactured and used—thermostats that simply allow you to raise, lower, and set temperatures without any automation. Determining if yours is actually a programmable model is not always easy.

For many Honeywell thermostats, the presence of a push-button "PROG" or "Set" key is the giveaway that the thermostat is programmable. Those that aren't programmable have nothing to set, and so they are missing this button. The photos here show the difference between a typical non-programmable thermostat and one that can be programmed.

A non-programmable thermostat.
credit: Honeywell
This thermostat has no "set" or "program" button, and is thus identified as manual model that is not programmable.
A programmable thermostat.
credit: Honeywell
The "SET" key identifies this Honeywell thermostat as a programmable model.

One the very latest models, you may find no buttons at all, but instead there is a touch-screen feature in which you'll read the "set" command in the screen itself.

Here are some popular Honeywell thermostat models and their functions. It is by no means an exhaustive list, but it does demonstrate the diversity available. It is likely that your thermostat is closely related to one of these:

Non-Programmable Models

  • Pro 5000 series (TH5110D, TH5320U, TH5220D): non-programmable thermostats with digital screens.
  • RTH5100B: A premium non-programmable thermostat with a digital screen.

Programmable Models

  • RTH221B: A basic 1-week programmable offering 1 program.
  • RTHL2310B: A basic 5-2 thermostat offering two programs.
  • RTH6450D: A 5-1-1 thermostat offering three programs.
  • RTH2510B1018: A seven-day programmable thermostat with digital screen.
  • RTH7560E: A seven-day programmable model with touch-screen controls.
  • RTH8580WF: A seven-day programmable model with WI-FI connectivity.

How to Set a Honeywell Programmable Thermostat

Because there are many variations in thermostat styles, it's impossible to describe the programming process for each and every one of them. However, they will all follow much the same process, so it should be an easy matter to interpret the following instructions, even if your thermostat doesn't exactly match.

Our instructions happen to be based on the Honeywell RTH6450D1009 5-1-1 thermostat, shown above, but virtually all Honeywell thermostat are programmed with a process that is similar, if not identical.

Step 1 Set the Time

Push the SET button until the time or day display begins to flash on the screen. Then use the arrow buttons to adjust the time up or down until the correct time-of-day is displayed. Press the DONE button to lock this time into the thermostat.

NOTE: On some thermostats, pressing the SET key a second time is what locks the time into the thermostat.

Step 2 Set the First Program

  1. Press the SET key, then press the key labeled "SET SCHEDULE". (On some thermostats, you press the SET key several times to toggle through the various functions on the thermostat.)
  2. Press the UP and DOWN arrow keys until the display flashes to the MON-FRIDAY WAKE display, then press NEXT.
  3. Use the UP and DOWN arrow keys to set the time you generally wake up during the Mon-Friday work week. When the proper time is set, press NEXT.
  4. Now use the UP and DOWN arrow keys to set the temperature you desire for that weekday wake-up time. When the correct temperature is displayed, press the NEXT button to lock in that temperature and move on to the next time period.
  5. Use the UP and DOWN arrow keys and the NEXT button to lock in times, then temperatures, for the next periods of the program: Leave, Return, and Sleep. This four-temperature program is standard on most programmable thermostats.

Step 3 Set the Next Program

Upon locking in the last temperature period for Mon-Friday, the next press of the NEXT key will activate the next program available on your thermostat. For our thermostat, this is the Saturday program. Program this in the same fashion (see step 2), and repeat until all programs are set. This may be only one additional program for a 5-2 thermostat or as many as six more for a seven-day thermostat.

Step 4 Completing the Program and Making Adjustments

A simple press of the DONE button locks in the program and closes the setup menu.

If you've made an error in the initial programming, or if your schedule changes and you need to adjust the program, the process is simple:

Press the SET SCHEDULE button, then toggle through the menu options by using the NEXT button and UP/DOWN arrow keys to toggle through the functions and make new settings. For example, let's imagine that you want to change both the time for waking and the temperature for that time of day. The key press sequence would look like this:

  1. SET CLOCK/DAY/SCHEDULE
  2. UP or DOWN arrow keys until WAKE period begins to flash on the screen
  3. UP or DOWN arrow keys until new wake time you desire is displayed
  4. NEXT
  5. UP or DOWN arrow keys until the desired temperature is displayed
  6. DONE (on some models, you may need to toggle through the other time periods and programs before the DONE key displays)

Step 5 Overriding the Program

What happens if you've stayed home for work some day, for example, and don't want the thermostat program to send the temperature down to 60°? Just press the arrow keys until the desired temperature is displayed on the screen. Your thermostat will display the word "TEMPORARY" on the screen, and the thermostat will then hold the temperature at that level. At the point where you want to resume the program, just hit the RUN SCHEDULE button.

Another way to override the program is to press the HOLD button, which will tell the thermostat to hold the temperature at the current level until you deactivate it.