A well-chosen air conditioner placed in the wrong spot will never perform the way it should.
The unit on your wall isn't the only factor in how well your air conditioning works. Where it sits, what faces it, and what's nearby all affect how hard it has to work — and how long it lasts. Poor placement can reduce cooling efficiency by 20–30%, accelerate wear on the compressor, and create noise problems that no amount of servicing will fix.
Where to put the indoor unit
The sweet spot for a wall-mounted indoor unit is 2.0–2.4 metres above the floor. At this height, cooled air is delivered at head level and falls across the occupied space. Too high, and the airstream misses people entirely. Too low, and you create a cold draught on anyone in the direct path.
Leave at least 15cm between the top of the unit and the ceiling — that's where the air intake is. Block it and the unit has to fight for every breath. Keep 20cm clear on each side. And mount it on a structural wall: a 24,000 BTU unit weighs 13–18kg with additional dynamic load from vibration.
Common mistakes to avoid
Don't install above a doorway (conditioned air escapes every time the door opens). Don't mount directly over a bed or sofa (cold draughts are uncomfortable even at the right temperature). Keep it away from heat-generating appliances — a TV nearby will confuse the temperature sensor and keep the compressor running past setpoint.
Where to put the outdoor unit
The outdoor unit needs space to breathe. The condenser draws ambient air across its coil and rejects heat outward. Obstruct either the air intake or the discharge, and the compressor has to work against higher pressure — which shortens its life significantly.
Minimum clearances: 30cm at the intake (back/side), 60cm on each side, 70cm in front of the discharge fan, and 150cm above the unit. Don't install in an enclosed alcove or against a wall directly in front of the discharge. When discharged hot air can't escape freely and curves back into the intake — called hot air recirculation — it can add 10–15°C to the effective ambient temperature the unit is working against.
Sun, shade, and South African summers
An outdoor unit in direct afternoon sun — particularly west-facing — can see the air temperature around it rise 8–12°C above actual ambient. That's the compressor working against air that's effectively 45°C on a 35°C Highveld afternoon. Shade helps significantly, provided it doesn't restrict the 150cm overhead clearance.
Keep it away from these things
Gas meters and LPG cylinders: minimum 3 metres. In a gas leak, the outdoor unit fan draws gas toward the unit and the starting relay can ignite it. Kitchen extraction exhausts and tumble dryer vents: minimum 3 metres. The grease and lint that accumulate on condenser fins are extremely difficult to remove and dramatically reduce heat transfer. Swimming pools and water features: minimum 3 metres, and specify coated coils. Chlorine is corrosive to standard aluminium fins over time.
Coastal installations
Within roughly 2–3km of the ocean, salt-laden air will corrode standard aluminium fins aggressively. Specify Blue Fin or Gold Fin coated condenser coils for coastal applications — the additional cost is a fraction of what a premature condenser replacement costs.
A Jet-Air consultant can assess your specific installation situation and recommend optimal placement before anything is drilled. Getting this right from the start is far cheaper than moving a unit that was placed incorrectly.