ecobee's Wi-Fi article splits offline into two cases: the thermostat is offline, or it keeps disconnecting. A search summary of its steps says that if the screen is on but the thermostat shows offline in the app, you should reboot your router and any extenders first and then reboot the ecobee. If the Wi-Fi signal strength on the thermostat is below 75 percent it may cause connection issues, so move the router closer or add an extender, and make sure the router broadcasts a 2.4 GHz network; the Smart Thermostat with Voice Control, Premium and Enhanced can also use 5 GHz.
The checks in more detail
Check the thermostat's own display: the Main Menu shows Wi-Fi status and signal strength, and a thermostat can keep heating and cooling from its display while offline. Check the wifi password, that the router is not blocking new devices and that the thermostat's date and time are right. If the thermostat is frequently disconnecting, look for interference from other electronics, an aging router and too many devices, and update the router's firmware. A thermostat that lacks power can also disconnect, so if the display flickers or reboots use ecobee's power article.
If you changed your router, use the change Wi-Fi article to reconnect. As a last step consider a reset, but write down HVAC settings first, since Reset All loses them. Compare how many devices in your home lost wifi together, since one device dropping points at the thermostat and several at the router. A thermostat that drops only in very hot or cold weather may be reacting to the load on the system, so note the outdoor temperature. Contact support with the model, firmware version and signal strength ready.
If the thermostat is offline right after the heating season starts, the first cold-start load can briefly disturb the wifi, so give it a full day and check power before rebuilding the connection. ecobee shows a signal strength percentage on the thermostat, so write it down at the thermostat's wall and again after moving the router, since the number turns a guess about distance into a measurement. Some homes have both a modem and a separate router, and restarting only one leaves the other holding a stale address, so restart both in order, modem first, and give the network a few minutes before the thermostat is asked to join again.
Differential
Likely causes of “ecobee thermostats is offline or unavailable”, and how to tell them apart
- 1
A weak wifi signal
What separates it The thermostat shows offline often because its wifi signal strength is below 75 percent
How to confirm Move the router closer, or add an extender, until the signal at the thermostat is above 75 percent
- 2
A router not restarted
What separates it The app shows the thermostat offline because the router has not been restarted for a long time
How to confirm Reboot the router first and let it settle, then restart the ecobee so it rejoins the network
- 3
A band problem
What separates it The thermostat cannot join the network because of the wifi band that it is trying to use
How to confirm Use a 2.4 GHz network, or a 5 GHz network on the models that support that band
- 4
A power problem
What separates it The thermostat drops off and reboots because the power reaching it is too weak to keep it stable
How to confirm Check the C wire is connected, or fit the Power Extender Kit, so that it has steady power
- 5
A changed router or password
What separates it The thermostat went offline right after you changed the router or the wifi password
How to confirm Reconnect it through the thermostat's wifi settings, and enter the new network name and password
Before you touch a setting
Record this first — changing settings destroys the evidence
- The signal strength shown in the thermostat's wifi settings
- Whether the display shows it online
- Whether you recently changed the router or its password
Try in this order
0 of 7 completedReboot router and extenders
ReversibleReboot the router and any extenders, wait for them to settle, then restart the ecobee thermostat.
Check signal strength
ReversibleCheck the signal strength in the thermostat's wifi settings, and aim for a reading above 75 percent.
Check the wifi band
ReversibleCheck the wifi band, since the thermostat needs a 2.4 GHz network, and some models also use 5 GHz.
Retype the password
ReversibleRetype the wifi password carefully and reconnect, since a small typing mistake stops it joining.
Check power
ReversibleCheck the power if the thermostat reboots, because a weak C wire can cause it to drop offline.
Update router firmware
ReversibleUpdate the router's firmware if the thermostat keeps disconnecting, since old software can cause drops.
Contact ecobee
ReversibleContact ecobee if the thermostat stays offline, and tell them the signal strength and the model.
Model-specific
What is true of this model and not of its siblings
- Premium and Enhanced
- Can use 5 GHz as well as 2.4 GHz.
- ecobee3 lite
- Uses 2.4 GHz wifi.
- Other models this page answers
- These steps also fit the Smart Thermostat Enhanced, ecobee3 lite.
Stop boundary
When this stops being a self-service repair
- !If the thermostat stays offline after a reboot and reconnect, contact ecobee support
- !If it reboots often, check the power supply to the thermostat, including the C wire
- !If you are unsure about wiring, contact an HVAC pro
Evidence ledger
Sources behind this answer
Offline and disconnecting steps.
Wifi setup and change.
Black screen and power.
Reset options.
The company and its products.
Exact questions
Common questions
What signal strength is good?+
A good signal strength is above 75 percent, and a lower reading can cause it to drop offline.
Which band?+
It uses a 2.4 GHz network, and some models can also use a 5 GHz network.
Can it work offline?+
Yes, it can still heat and cool from the display when offline, though the app cannot reach it.
Does power affect wifi?+
Yes, poor power can cause reboots, and each reboot drops the wifi connection for a short while.
Should I reboot the router first?+
Yes, reboot the router first, because that fixes many connection problems with no other changes.
Does a reset erase HVAC settings?+
Yes, a reset erases the settings, including the heating and cooling equipment settings.
Can extenders cause drops?+
Yes, some extenders can cause drops, particularly if they have the same name as the main router.
Which app controls an ecobee thermostat?+
You control it from the ecobee app on your phone, and you can also make most changes on the thermostat's own display.
Where do I find the firmware version?+
On the thermostat, open the Main Menu and choose About, where the software version and the model are listed.
Do ecobee thermostats update themselves?+
Yes, they update automatically when they are connected to wifi, so a thermostat that is offline cannot get new software.
What is a SmartSensor?+
A SmartSensor is a small room sensor that reports the temperature and whether the room is occupied, back to the thermostat.
How far can a room sensor be from the thermostat?+
A sensor can sit up to about sixty feet from the thermostat, though walls and floors between them can shorten that range.