Cooling: moving heat out of the room
In cooling mode, the indoor unit absorbs heat from the room and the refrigerant circuit carries that heat to the outdoor unit. The indoor unit also removes some moisture from the air, which can improve comfort in humid conditions.
Heating: reversing the process
In heating mode, a reversible system extracts heat from outdoor air and releases it through the indoor unit. This is why many modern air conditioners are described as air-to-air heat pumps.
The heat arrives as warm moving air rather than through radiators. Unit position, fan speed and room layout therefore affect how the space feels. For room-by-room design support, see our domestic air-conditioning service.
What efficiency figures can—and cannot—tell you
Product data uses seasonal efficiency measures that allow equipment comparison under test assumptions. Real energy use still depends on outdoor temperature, target temperature, building heat loss, system sizing, hours of use and user behaviour.
Using the system sensibly
Choose a stable set point
Extreme set points do not make the room reach comfort instantly. A realistic target and appropriate fan setting usually give steadier results.
Condition the occupied zones
Room-by-room control can reduce unnecessary operation, but the building and system should still be used in a way that avoids comfort or moisture problems elsewhere. If several rooms need treatment, compare single-split and multi-split systems.
Keep airflow clear
Follow manufacturer guidance for filter care and do not block indoor or outdoor units. Arrange appropriate servicing for the system and its use; our air-conditioning maintenance guide covers the signs and routine tasks to know.
Air-to-air systems heat and cool indoor air. They do not normally provide domestic hot water, so the rest of the property’s heating and hot-water strategy still matters.