This post explains the most common symbols on air conditioning remote controls. It shows which symbols control heating, cooling, airflow, and automation, and why using the wrong one often causes cold air or poor performance.
You press a button.
A symbol appears.
The system behaves differently.
Most air conditioning problems start here. People change settings without knowing what the symbols mean. The system responds correctly, but not in the way you expect. Understanding the symbols removes most confusion and avoids cold rooms in winter.
Remote controls rely on symbols to save space.
Manufacturers assume users understand them.
Most users do not.
Different brands use similar symbols but place them in different positions. Some remotes show multiple icons at once. Others hide modes behind menus.
The meaning matters more than the design.
The mode symbol controls everything.
If the mode is wrong, nothing else matters.
This symbol decides whether the system heats, cools, or simply moves air. Temperature settings only work inside the chosen mode.
Always check the mode symbol first.
Heating mode is usually shown by a sun symbol or the word HEAT.
When this symbol appears, the system is allowed to produce heat. Warm air may not arrive immediately, but heating is active.
If you do not see a sun or HEAT, the system is not heating.
Cooling mode is usually shown by a snowflake or the word COOL.
This tells the system to remove heat from the room. If this symbol stays active from summer, the system will continue cooling even in winter.
This is the most common reason air conditioning feels cold at 21°C.
Auto mode is usually shown by the word AUTO or a combination of symbols.
In this mode, the system decides whether to heat or cool based on sensor readings. This can change throughout the day without warning.
Auto mode often causes cold air in winter due to sunlight, cooking, or people raising the temperature near the sensor.
The fan symbol shows fan only mode.
In this mode
Air moves
No heating occurs
No cooling occurs
The system simply circulates room air. This often feels cold in winter and is frequently selected by mistake.
Fan speed is shown by bars, curved lines, or multiple fan icons.
More bars or lines mean faster airflow.
Fewer bars mean slower airflow.
Fan speed changes how heat spreads, not how much heat is produced.
Medium fan speed usually works best for heating.
Dry mode is usually shown by a water droplet.
This mode reduces moisture, not temperature. It often runs the fan gently and can feel cool even though the temperature setting looks normal.
Dry mode is not designed for heating.
The swing symbol controls airflow movement.
It moves air up and down or side to side.
It does not control temperature.
Incorrect airflow direction can make heating feel weak by pushing warm air away from occupied areas.
Timer symbols look like clocks.
Timers can
Turn the system on
Turn it off
Change behaviour overnight
Active timers often explain why heating stops unexpectedly in winter.
Always check for a clock symbol if behaviour seems random.
These combinations appear frequently during support visits.
Snowflake with high temperature
AUTO with changing icons
Fan symbol with no heat symbol
Clock symbol active overnight
Multiple symbols visible at once
Each one changes how the system behaves.
A simple approach works best.
Select the sun or HEAT symbol.
Set a sensible temperature.
Use medium fan speed.
Avoid AUTO mode.
Check timers are off.
This prevents most winter issues.
If heating mode is confirmed and the room still does not warm after 15 minutes, the issue may sit elsewhere.
Possible causes include
Low outdoor temperatures
System sized mainly for cooling
Restricted airflow
Installation related factors
These need assessment.
Contact a specialist if
Heating symbol is active with no warmth
The remote display does not change
Symbols flash or error codes appear
The outdoor unit does not operate
Before calling, note which symbols are visible and how long the issue has been happening.
This helps resolve the issue faster.
Further residential air conditioning guidance is available at
https://www.climateworks.co.uk/residential-air-conditioning
UK Government guidance on heat pump operation
https://www.gov.uk/guidance/heat-pumps-how-they-work
Building Regulations Approved Document L
https://www.gov.uk/government/publications/conservation-of-fuel-and-power-approved-document-l
ClimateWorks residential support records from installations across Hampshire, Berkshire, Surrey, and Oxfordshire between 2022 and 2025
Dr Julian Carter
Technical and Compliance Director
ClimateWorks
Dr Julian Carter has over 20 years of experience in building services engineering, air conditioning system design, and regulatory compliance. He advises on residential and commercial projects across the UK, covering system selection, installation standards, commissioning, and real world performance.
As Technical and Compliance Director at ClimateWorks, he oversees technical governance, installer training, fault diagnosis, and customer education. His work focuses on reducing user related issues, improving system reliability, and ensuring air conditioning systems perform consistently throughout their service life.
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