Why would you wish to calibrate the temperature reading on a Honeywell thermostat? Perhaps you’ve noticed that your thermostat reads warmer or cooler than the room actually feels, and you’d like to bring the thermostat temperature reading more inline with the reality of your particular home. Or, maybe the thermostat is installed on a particularly warm or cool wall in your home. If the thermostat is on a warmly biased wall, the rest of the house may feel too cold during the winter, and too warm during the summer. If it’s located on a cool wall, then the reverse might be true; the rest of the home feels too cold in the summer, and too warm during the winter.
To eliminate these problems, and compensate for situations where the thermostat reading is simply inaccurate, or it is accurate but located in particularly warm or cool places in the home, calibration of the sensed temperature at the thermostat is in order. It’s a simple process really, so long as your particular thermostat provides an option to adjust the temperature offset between what the thermostat senses, and what the actual room temperature is, or at least, what you think it feels like. Honeywell provides this offset adjustment setting in its 9000 series RTH9580WF internet controlled thermostat, which is the one we’re currently using in our home. So, we’ll discuss next, how to adjust this offset for better performance from that thermostat. However, this discussion applies to the other series 9000 thermostats as well.
The thermostat calibration process involves two main steps. First, you determine how far off the sensed thermostat temperature is from the actual room temperature. Then, you adjust the thermostat temperature offset parameter accordingly. Simple, right? Right!
Determining Actual Thermostat Temperature Offset
10. Obtain an accurate thermometer. For this demo, we used a refrigerator freezer thermometer, which works reasonably well. However, we recommend that you obtain a glass thermometer that is designed to read temperatures in the common household temperature range, say from 50 to 90 degrees. Not only does this type of thermometer provide more accurate readings, but its reading will likely be larger and thus easier to see clearly.
2. Place the thermometer near the thermostat; as close as practical to it. In the picture above, we hung our fridge freezer thermometer on the same wall as the thermostat, on a nearby nail.
3. Allow temperature readings to stabilize. Particularly if you brought the thermometer in from a cooler or warmer location, let it hang for twenty minutes to a half hour.
4. Read the thermostat and thermometer temperatures. In our case, the thermometer read the room at 76 degrees F, while the thermostat read it at 77 degrees F.
5. Calculate the actual temperature offset. Now assuming that the thermometer is the more accurate of the two readings, then this means that the actual room temperature is -1 degree offset from what the thermostat is sensing. We’ll need this in the next task; calibrating the thermostat temperature offset accordingly.
Calibrating Honeywell Thermostat Temperature Offset
The -1 degree actual temperature offset that we determined above with the thermometer can be programmed into many Honeywell smart thermostats. Here, we demonstrate how to do it on our 9000 series RTH9580WF Wi-Fi thermostat. You start at the Home screen, as displayed next.
1. Tap the MENU button on the Home screen. This brings up the thermostat’s main menu, as shown next. We then scrolled down using the arrow buttons, to bring the Preferences item into view.
2. Tap the Preferences button, as pointed at by the pink arrow in the previous picture. The Preferences screen then displays, as shown next. We then scrolled down using the arrow buttons, to bring the Advanced Preferences item into view.
3. Tap the Advanced Preferences button. This displays the first in a series of advanced preference settings screens; the Scheduling Options screen, as shown next.
4. Repeatedly press green Next button until you reach the Indoor Display Offsets settings screen, as shown next.
5. Adjust indoor temperature offset. Use the UP and DOWN arrow buttons to adjust the indoor temperature offset. These are circled in pink, in the previous picture. In our case, you’ll recall that our temperature offset was -1 degree F. So in our case, we tapped the DOWN arrow once to enter -1 degree, as shown next.
6. Press the red Done button. You will then be asked whether you actually wish to save your preferences changes, as shown next.
7. Press the green Yes button. The Saving Changes screen briefly appears, as shown next.
After the new temperature offset setting has been saved, you
8. Tap the Previous Menu button. Doing so returns you to the Main Menu screen, as shown next.
9. Tap the Home button. This completely finishes the temperature offset adjustment operation, and returns you to the thermostat’s Home screen, as shown next. Note that this screen appears as it did before we changed the temperature offset. E.g. The current temperature still reads 76, and so does the set temperature. However, our apartment now feels a little warmer (one degree warmer, in fact). Now had we made a bigger change, such as -4 degrees, then the current temperature reading would have shown a lower number. However, since our change was just -1 degree, the furnace had enough time to raise the room temperature to make up for that one degree, and so, the current temperature reading stayed the same in this case.
10. You’re done! For a given temperature setting, your climate control system will, for negative temperature offsets, keep your place a little warmer, and for positive temperature offsets, a little cooler. Enjoy.
- Honeywell Smart WiFi Thermostat Manual RTH9580WF
- How to Change Time and Day on Honeywell Wi-Fi Thermostat RTH9580WF
- How to Clear Settings on Honeywell Thermostat RTH9580WF
- How to Lock and Unlock Honeywell Thermostat RTH9580WF
- How to Set Honeywell Thermostat Temperature RTH9580WF
- Troubleshooting Honeywell Thermostat WiFi Problems RTH9580WF
- 2017-03-15: Originally published.