What the snowflake icon on a thermostat means, including when it blinks

A steady snowflake means cooling mode

The Department of Energy describes a thermostat as a control system to regulate the amount of cool air that is distributed.

On the White-Rodgers 1F89-0211 thermostat, the snowflake is displayed without flashing when the system switch is in the "COOL" position. The flame icon plays the same role for heat.

On Honeywell's FocusPRO S200, the words "Cool On" appear in the lower right of the display when cooling is running. Read your own model's manual to see which icon or words it uses. For the wiring and switching behind the screen, see how a thermostat works.

Why many thermostats blink the snowflake

The Department of Energy says the cooling coils remove heat and humidity from the air using refrigerant.

Honeywell Home says that if the "Cool On" words or the snowflake icon are flashing, the thermostat is in delay mode. It says this delay protects your equipment from short cycling.

Carrier, another equipment maker, says a flashing "Cool On" means the thermostat has received a signal to cool your home but is waiting before turning on the air conditioner. Carrier also says rapid restarts can cause pressure imbalances that damage the compressor.

Honeywell Home explains where the wait comes from. Its minimum off timer is activated after the compressor turns off. Honeywell's FocusPRO S200 manual says that when the compressor protection feature is engaged, you should wait a few minutes for the system to safely restart.

Not every brand blinks for the same reason

On the White-Rodgers 1F89-0211, the snowflake flashes when the thermostat is calling for cool. The delay shows up differently: the setpoint, meaning the temperature you chose, flashes when the thermostat is in lockout mode, which White-Rodgers says prevents the compressor from cycling too quickly.

Other models show words during the delay. Honeywell's FocusPRO S200 shows "WAITING FOR EQUIPMENT" during its compressor delay. The White-Rodgers 1F83C-11NP shows "Starting Soon" when its compressor lockout feature is operating.

White-Rodgers adds that some newer compressors already have a time delay built in. On the 1F89-0211, the thermostat's own delay sits in its installer and configuration menu, where it can be set off or on. White-Rodgers says your compressor manufacturer can tell you if the lockout feature is already present.

How long a normal blink lasts

Honeywell Home says the delay can be up to five minutes under normal operating conditions. Its advice for a flashing "Cool On" is to give the system five minutes before expecting it to start.

Carrier says most modern thermostats include a delay of three to five minutes. It says the air conditioner (AC) should start within that window under normal conditions. White-Rodgers manuals describe a delay of up to five minutes before the compressor turns on.

So the first step is simply to wait.

Checks a homeowner can make

Carrier says to make sure the system mode is set to "Cool," not "Heat," "Fan" or "Off". It also says to confirm the target temperature is lower than the room temperature. For starting points on that number, see thermostat settings.

Check the air filter as well. Carrier says to replace it if it looks gray, clogged or heavily dusty. ENERGY STAR says a dirty filter can damage your equipment, leading to early failure.

If anything beyond these checks seems wrong, see why an AC will not turn on before touching anything else.

When the blinking means a problem

Carrier says that if the message keeps blinking past five minutes with no cooling, something is preventing the air conditioning system from starting. Honeywell Home says a delay longer than five minutes may point to an issue with the voltage to the thermostat. It says a professional contractor could check that voltage and look for shorted wires.

Carrier also says to call for help if the AC unit makes unusual sounds, leaks, or blows warm air. It adds that low refrigerant and compressor faults must be diagnosed and repaired by a licensed professional. If the screen itself is acting up, see signs a thermostat is going bad.

None of these manufacturer sources mentions Florida.