Placing the indoor head
The indoor head's job is to throw conditioned air across the whole room evenly. That means:
- High on the wall, with breathing room. Heads mount near the ceiling and need clearance above and to the sides (the manual gives exact figures) so they can pull air in and push it out without starving themselves.
- Centered on the space, aimed at the living zone. Put it where its airflow reaches the whole room and blows toward where people sit and sleep - but not directly at them. A head blasting straight onto a bed or a desk gets switched off; one that washes the room evenly gets left alone.
- On an interior or accessible exterior wall. It needs a clear path for the line set to reach the outdoor unit through the wall, and it drips condensate, so it has to reach a drain (gravity or a pump).
- Not above electronics or over a doorway. Avoid mounting where a rare drip or the airflow causes problems.
Get the room size right first, because an oversized or undersized head placed perfectly still won't perform - see the sizing guide.
Placing the outdoor unit
The outdoor condenser is more forgiving on looks but pickier on function:
- Open airflow. It needs to breathe - a couple of feet of clearance on the fan side and above, away from tight corners, dense shrubs, or anything that recirculates its own exhaust.
- Short, straight line-set run to the head. The closer and more direct the path, the better - long or convoluted runs cost efficiency and can require adding refrigerant. Plan the two units' positions together.
- Off the ground, level, and stable. On a pad, bracket, or stand so it clears drainage, debris, and - in cold climates - the snow line. See wall brackets and stands.
- Away from bedroom windows and property lines. It's quiet, but not silent - don't put it right under a bedroom window or tight against a neighbor's wall. Anti-vibration pads help if it must mount near living space.
- Serviceable. Leave room for a technician to reach it. You'll thank yourself at the first maintenance visit.
The one rule that ties it together
Plan both units at once, and keep the run between them short. The single biggest placement mistake is picking a pretty spot for each unit independently and ending up with a long, winding line set. Decide the pair together, minimize the distance, and you protect both efficiency and your install cost. When you're ready for the actual process, see how to install a mini split.
FAQ
Where should I mount the indoor unit? High on the wall, centered on the room with clearance around it, blowing toward the living area but not directly at a bed or seat - and on a wall where the line set can reach the outdoor unit and the condensate can drain.
Where should the outdoor unit go? Somewhere with open airflow and service access, off the ground on a pad, bracket, or stand, with the shortest practical line-set run to the indoor head - and not right under a bedroom window.
How far apart can the indoor and outdoor units be? Every system has a maximum line-set length in its manual; stay well under it. Shorter, straighter runs are better for efficiency, and going past the rated length can require a pro to add refrigerant.
Can the outdoor unit go on the roof or in the attic? The outdoor unit mounts outside with open air - a roof or wall is fine with proper support and clearance; an enclosed attic is not, since it needs to exhaust heat to the outdoors.