A split air conditioner has two halves joined by two pipes: a quiet indoor unit on the wall and a louder outdoor unit that dumps heat. Use the buttons to look inside and follow the refrigerant around its loop between them.
A split air conditioner is one cooling system built as two boxes joined by two pipes. The quiet half — the indoor unit — hangs on the wall of the room. The loud half — the outdoor unit — sits outside. They share a sealed loop of refrigerant, and together they carry heat out of the room.
Inside the indoor unit an evaporator coil gets very cold while a blower pushes room air across it; the air gives up its heat and comes back cooler. That heat is not destroyed, though. The refrigerant carries it through the wall to the outdoor unit, where a condenser coil and a fan release it into the outside air. Then the refrigerant returns to start again.
From the outside you see a neat white box on the wall and a humming grille on the ground outside. All the moving parts and the phase changes happen behind those covers, so showing the casings only faintly makes it clear where the heat actually goes.
One idea holds the whole machine together: the indoor coil is made colder than the room so heat flows into it, and the outdoor coil is made hotter than the outside air so heat flows out of it. The compressor and the expansion point are what keep one side cold and the other side hot.
The outdoor compressor is the pump that drives the whole loop. It squeezes the refrigerant gas, raising its pressure, and squeezing a gas also heats it. The refrigerant leaves the compressor as a hot, high-pressure gas — hotter than the outside air, which is exactly what it needs to be.
The hot gas flows through the condenser coil in the outdoor unit. Because the refrigerant is hotter than the outside air, its heat leaks out and the coil feels warm. The outdoor fan pulls air across the coil to speed this up. As it loses heat, the refrigerant cools and turns back into a liquid.
The liquid refrigerant travels indoors along the thin liquid line. At the indoor unit it passes through a narrow expansion point, a restriction that chokes the flow and drops the pressure sharply. That sudden drop is what makes the refrigerant cold right before it reaches the evaporator.
The cold refrigerant enters the evaporator coil, which is now colder than the room air. The indoor blower draws warm room air across the coil, so heat flows from the air into the refrigerant. The refrigerant absorbs that heat and boils back into a gas, and the room air — having lost its heat — blows back out cooler.
The warmed gas leaves the indoor unit along the thicker suction line and travels back through the wall to the compressor. The loop is now complete: what left as hot gas has come home as warm gas, ready to be squeezed again.
A thermostat or wall controller reads the room temperature and compares it with your setpoint. When the room is cool enough it slows or stops the compressor; when the room warms again it restarts the loop. That on-and-off trimming is what keeps the room near the temperature you chose.
A split system separates the noisy parts from the quiet ones. The compressor and condenser sit outside, and only the evaporator and blower stay indoors on the wall.
No. Like a fridge, it moves heat. The indoor coil takes heat out of the room air and the refrigerant carries it outside, where the outdoor coil releases it.
They carry the refrigerant back and forth. A thin liquid line feeds cooled liquid indoors, and a thicker suction line returns warmed gas to the outdoor compressor.
That warm air is the heat taken from your room. The condenser coil and fan simply dump it into the outside air, which is why the unit feels hot.
A thermostat or wall controller reads the room and compares it with your setpoint. When the room is cool enough the compressor slows or stops, and it restarts when the room warms again.
SEER stands for Seasonal Energy Efficiency Ratio. It measures how much cooling a unit delivers for each unit of electricity over a typical cooling season, so a higher number means the same cooling for less power.
For a split system, the copper lines and their joints are commonly checked about once a year for leaks or damaged insulation. This is routine maintenance advice, since a sealed loop should not lose refrigerant on its own.
A ductless mini-split has no ducts and pairs one outdoor unit with one indoor unit per room it serves. Central AC uses a network of ducts to distribute cooled air from a single indoor unit to the rooms in the home.