The answer
Why plan the drain before choosing an air-conditioning unit position?
Cooling creates water that has to drain away. A downhill pipe is often simpler and quieter than a pump, but the route must avoid leaks, freezing and discharge where it could bother neighbours.
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Can the water run downhill?
A drain needs enough slope all the way out. A long flat or hidden section can hold water, smell or leak later.
02 / 03
Would a pump be noisy?
If water cannot drain downhill, a small pump may be needed. Ask where it will go, how you will reach it for cleaning and whether you will hear it in the room.
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Where will the water end up?
Do not let it drain onto a path where it could freeze, onto a wall it could stain or into a neighbour's space. The installer should show the final outlet on the plan.
Where will the water drain away?
Cooling removes moisture from indoor air. That water needs a reliable route to a suitable discharge point. Gravity drainage is often simpler, but it needs enough fall along the whole pipe. A long horizontal run or hidden low point can collect water and eventually leak.
If a pump is unavoidable, allow for its sound, power, cleaning access and a response to failure. Agree where the water ends up; discharge onto a path, neighbour's area or sensitive façade can cause nuisance or damage. Draw the drain before approving the indoor-unit location.
What to check next
Your next steps
Where we checked the facts
Check the original information.
These official pages back up the rules and technical details above. They can change, so check them again before spending money or starting work.
Apply this to your own property
Which rooms could you heat or cool?
A free survey checks the rooms you want to heat or cool, equipment positions and what may fit your property.