I've got a "portable AC unit" which is a free-standing unit, not a permanent installation like a high wall split system.

They require to be vented to the outside world, otherwise they simply don't work. I intend to use this to cool down my garage/workshop which has no normal windows.

What is the best way to vent this AC unit?

The options are :

  1. Run the large diameter spiral hose straight up, and over the brick wall, then down through a soffit vent.
  2. Same, but tee the hose into an existing extractor fan's hose (for venting a laundry space, rarely used)
  3. Same, but simply run the hose into the roof cavity and let it heat an already hot space.

Drilling a vent:

  • through the wall is not easy because its brick-lined on the outside
  • through the person-door is impossible because its entirely double glazed and opens back against a wall
  • through the car door is unfeasible because it moves up and down
  • through the roofing will break the waterproof layer, and I'd rather not.

Dimplex portable AC

  • I don't yet have any condensate coming from the unit, but its dry here now so this may increase later on. – Criggie Dec 25 '19 at 22:18
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    Not sure what you should do, but definitely don't "Same, but simply run the hose into the roof cavity and let it heat an already hot space." – manassehkatz-Moving 2 Codidact Dec 25 '19 at 22:30
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    remove a brick from the wall and vent there. – Jasen Dec 25 '19 at 22:31

Update - my temporary install has been a 6" hose straight up through a manhole in the ceiling.

I've used some old suspended ceiling tiles to block the manhole other than a 6" hole for the hose. This admittedly rough solution knocks ~5 degrees off the room temperature, but sadly does vent straight into the roof space.

For the condensate hose, I drilled a 6.5mm hole through the plastic and brought it out the side into a spare 1.5L PET bottle. So far there has been zero water in the catch bottle.

The next plan is to get more hose and join the ceiling panel to an existing soffit vent - I temporarily reallocated the ceiling vent from a laundry, which we never used.

Was it worth doing? Had I paid full price for this thing, definitely not. But it was quite cheap at $74 NZ so it seems adequate to cap the temperatures.

This would have been so much easier if the target room had a window.

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    Don't vent in to the attic, even with a condensate drain. Those AC units put the condensate tray in the path of the hot exhaust, and even with an open drain you will get significant humidity in the hot exhaust. – longneck Jan 14 '20 at 19:50
  • @longneck there is a condensate hose - about 8mm OD and 6mm ID. By design its supposed to route along the air tube and out a window, but I've brought it out the side of the hose and dropped into a bottle instead. There's never been any water in it, the workshop doesn't have many sources of dampness. – Criggie Jan 25 '20 at 6:49
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    I understand that there is a hose, but those AC units put condensate in to the hot exhaust. There's a reason you're not seeing anything in the bottle: it's going in to your attic. – longneck Jan 26 '20 at 1:07
  • @longneck so what's the point of the little hose at all ? – Criggie Jan 26 '20 at 2:05
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    Inside the air conditioner, the condensate drips in front of the fan that pushes out there hot air. Any water that doesn't get immediately evaporated and sent out the exhaust drops in to a tray. The water in that tray evaporates on it's own from the ambient air temperature, and newer models have a little paddle wheel that throws water from the tray in front of the exhaust fan. The little hose connects to the tray, but in low humidity environments all the water gets exhausted before the tray fills up enough to exit through the hose. – longneck Jan 27 '20 at 0:38

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