Your Honeywell thermostat schedule suddenly stopped following the temperature settings you programmed, leaving your home too hot or cold at the wrong times. This frustrating issue can spike your energy bills and disrupt your daily comfort, but you can usually fix it yourself in just a few minutes.
Step-by-Step Fixes
Step 1: Check if Schedule Mode is Actually Enabled
Press the “Schedule” or “Menu” button on your thermostat display. Look for text that says “Following Schedule” or a small clock icon. If you see “Manual” or “Hold” instead, your thermostat isn’t using the programmed schedule at all.
To re-enable scheduling:
- Press “Schedule” or “Run Schedule”
- Select “Following Schedule” from the menu
- Confirm by pressing “Done” or “Select”
This simple oversight happens more often than you’d think, especially after power outages or when someone manually adjusted the temperature.
Step 2: Clear Any Temperature Holds
Temporary holds override your schedule without you realizing it. Check your display for words like “Temporary Hold,” “Permanent Hold,” or “Hold Until.”
To remove holds on most Honeywell models:
- Press “Cancel” or “Run Schedule”
- If that doesn’t work, press and hold the center button for 5 seconds
- For touchscreen models, tap “Cancel Hold” at the bottom of the screen
Your thermostat should immediately return to the scheduled temperature for the current time period.
Step 3: Verify Your Actual Schedule Settings
Your schedule might be programmed incorrectly without you knowing it. Access the schedule review mode to check each time period.
Navigate to schedule settings:
- Press “Schedule” or “Menu”
- Select “View Schedule” or “Edit Schedule”
- Review each day, paying attention to:
- Wake, Leave, Return, and Sleep times
- Temperature settings for each period
- AM/PM settings (12:00 PM vs 12:00 AM confusion is common)
Many users accidentally set 6:00 PM as 6:00 AM, wondering why their heat kicks on at dinner time instead of morning.
Step 4: Check Your Clock and Calendar Settings
Wrong date or time settings make your thermostat run Monday’s schedule on Wednesday, or activate nighttime temperatures at noon.
To verify time settings:
- Press “Menu” or “Settings”
- Find “Clock” or “Date/Time”
- Confirm the current time, day, and year show correctly
- Adjust if needed, remembering to set the correct year (2025)
Some Honeywell models lose time settings after extended power outages, defaulting to January 1, 2000.
Step 5: Perform a Schedule Reset
If your schedule still misbehaves, corrupted programming might be the culprit. Reset just the schedule without losing other settings.
For most Honeywell thermostats:
- Navigate to “Menu” then “Preferences”
- Select “Schedule Reset” or “Restore Default Schedule”
- Confirm the reset
- Reprogram your desired schedule from scratch
This process takes about 10 minutes but often resolves mysterious scheduling glitches.
Step 6: Update or Reinstall Smart Thermostat Apps
For WiFi-enabled Honeywell models like the T9 or T10 Pro, app synchronization issues can break scheduling.
Fix app-related problems:
- Open your Honeywell Home app or Total Connect Comfort app
- Check for app updates in your phone’s app store
- Log out and log back in to refresh the connection
- If problems persist, delete and reinstall the app
- Re-link your thermostat using the setup wizard
Likely Causes
Cause #1: Power Interruptions Reset Your Settings
Brief power outages or electrical work can scramble your thermostat’s memory, especially in older models without backup batteries. Your schedule might still exist but with corrupted time stamps or temperature values.
Check for this by looking at your thermostat’s time display. If it shows the wrong time or a blinking 12:00, you’ve found the problem. Install fresh AA or AAA batteries (depending on your model) to maintain settings during future outages. Then reset your clock and review all schedule settings.
Cause #2: Multiple Users Making Conflicting Changes
In households with several people adjusting the thermostat, someone might have created a permanent hold or changed the schedule without telling others. Smart thermostats compound this issue when multiple family members have app access.
Review your thermostat’s history or logs if available. For app-connected models, check who has access permissions. Consider setting up a schedule lock feature (found in advanced settings on many models) that requires a code to change programming.
Cause #3: Firmware Glitches in Smart Models
WiFi-connected Honeywell thermostats occasionally develop software bugs that affect scheduling. These might appear after automatic firmware updates or when your home internet connection becomes unstable.
Check your firmware version in the thermostat’s “About” menu. Compare it to the latest version on Honeywell’s support website. If outdated, update through the device menu or app. If already current, try a factory reset as a last resort, though this erases all settings.
When to Call Expert Help
Contact a professional HVAC technician when your thermostat shows error codes, makes clicking or buzzing sounds, or fails to control your heating and cooling even in manual mode. These symptoms suggest wiring issues or equipment failures beyond simple programming fixes.
Call Honeywell support directly if your thermostat is under warranty and you’ve tried all troubleshooting steps. They can diagnose model-specific issues and authorize warranty replacements when needed. Professional help is ideal for complex zoning systems or when your thermostat connects to humidity controls, ventilation systems, or multi-stage equipment.
Copy-Paste Prompt for AI Help
Use this prompt for additional troubleshooting assistance:
“My Honeywell thermostat model [insert model number] is not following its programmed schedule correctly. The schedule shows [describe what you see], but the actual behavior is [describe what happens]. I’ve already tried [list what you’ve attempted]. The thermostat was installed in [year] and worked fine until [when problem started]. My home has [type of heating/cooling system]. What specific steps should I try next?”