Reset a Honeywell thermostat filter reminder

Choose your exact thermostat model to find its filter-reminder reset steps after replacing the filter. Other models get a manual-finding path.

Match the full thermostat model

Check the model on your manual or thermostat label. A similar faceplate or “Pro Series” name is not enough. Replace the filter before clearing its reminder.

Six verified models. This clears a maintenance timer, not thermostat schedules or equipment settings.

MODEL-SPECIFIC MAINTENANCE

The same alert does not mean the same buttons

Supported T6 Pro programmable models use an alert menu. FocusPRO N100 models use a five-second button combination. Match the full model before following either sequence.

T6 Pro programmable

TH6210U2001, TH6220U2000 and TH6320U2008. A trailing /U on the product listing is a sales suffix.

  1. Replace the air filter before clearing its reminder.
  2. Press Menu. Use the arrows to find ALRT, then press Select.
  3. Find REPL / Replace Air Filter. Confirm that it is the filter reminder, then press Select.
  4. Use the arrows to choose CLER, then press Select to clear the reminder.

SNZE postpones the reminder for seven days; it does not clear completed maintenance. This is not the sequence for T6 Pro Smart, Z-Wave or European T6 models.

T6 Pro manual, English page 7 ↗

FocusPRO N100

TH1110U4000, TH1210U4001 and TH1320U4002.

  1. Replace the furnace filter first. This procedure is for the Replace Filter reminder (code 181).
  2. Press and hold the upper-left and lower-right buttons together for five seconds to reset the filter timer.
N100 user guide, English first page ↗

If your model is not listed

Use the exact model number to find its official user guide. Other Honeywell thermostats can use different reminder controls. Do not substitute a factory reset, change installer settings or remove batteries to try to clear a filter timer.

Find Honeywell thermostat support ↗

Filter reminder questions

Why is the reminder still there after I changed the filter?

The documented reminders use run time or calendar time. Replacing the filter does not automatically clear their timer; use the sequence for your supported model.

Does code 181 always mean the same thing?

In the supported N100 guide it is the Replace Filter reminder. The linked T6 alert reference identifies 181 and 182 as filter 1 and filter 2 reminders. Do not apply this interpretation to an unverified model.

What if another alert remains?

Use the manual for that exact alert. Some equipment or sensor alerts cannot be cleared as maintenance reminders and may require service. These filter steps do not diagnose those faults.

Sources and coverage

Official manuals checked October 14, 2026. Six exact models are supported; other families receive no reset sequence.