This is the simplest solution, and it’s what I’ve begun doing to avoid confusion. I say turn up/down the temp.
That being said, turning up the air means making it cooler. If someone were to say “Crank up the AC!” would you be confused? To me, that means make it colder. So saying “Turn up the AC” means the same thing.
Down if there’s a thermostat, up if there’s just an arbitrary dial.
AC up, thermostat down.
My way of being clear is just to precede the request with a statement. “I’m cold. Can you turn up the A/C?” “It’s getting warm in here. Turn the air down a smidge.” Sure, I may use “temp” instead of air or A/C, but I’m far from consistent.
And, if someone says it in an ambiguous way, I guess, but confirm. “Can you turn up the air?” If it feels warm or they look hot, I say “Oh, are you hot?” Or the other way around. I’m usually right. And they usually say down for lowering the temperature, while saying up to raise it, unless they are older–in my experience.
Granted, it’s been a while since I’ve heard anyone I didn’t already know ask. Though this is also what other people I know have said. I’m surprised at the diversity of answers.
Cool. 
Depends on the AC unit.
Since mine has a temp setting rather than a fan setting, mine goes down.
I get why the question needs asking. I cannot answer the poll because my request usually goes something like this:
“Could you turn the air up? I mean, higher? Not up, up. You know, make it cooler?”
mmm
Saying “up” when you want to be colder is the textbook definition of being too smart for your own good.
At least most air conditioner controls are clearly marked. What gets me are refrigerators. Those are usually marked 1 to 10, with the “explanation” of “10 = max, 1 = min”. Well, yes, I was awake in 1st grade math, but is 1 the minimum temperature, or the minimum amount of refrigeration?
I ask for clarification if someone talks about it and it isn’t obvious. I myself talk about adjusting the temperature to make it “hotter” or “colder” if I think about it beforehand which I don’t always. When I say “up” or “down” I use either interchangeably.
I voted Down, but my hubby would have voted Up.
Typically on an appliance, when you turn it up, you’re making it do what it does with more intensity. For an air conditioner, that is making air colder.
Right. You turn the temperature (setting) down which is turning the AC up.
“I’m too hot, please address this.” Is what I’ve said at work when a dyslexic employee had trouble understanding things like this.
Well, I’m glad to see that there is no consensus on this. Mainly because every time my wife asks me to turn the AC up/down I always have to ask if she wants it colder or warmer.
When you turn the volume setting down, are you turning the TV up?
An “AC” can’t go up or down. It can only be on or off.
When someone says: “Turn the TV down” that’s shorthand for: Turn the volume on the TV down.
When someone says: “Turn the AC down”, that shorthand for: Turn the temp down on the AC.
Agreed. And everyone who thinks otherwise is wrong. It says so in the Bible.
I decided to run a similar, but not identical poll on twitter.
If you turn the air conditioner up, the room gets:
21% hotter
79% colder
You are (IMHO) confused with the idea being expressed. If the appliance is being asked to produce more of what it produces you are turning it up. One the things a TV produces is volume; when you turn the TV up it gets louder. You turn the volume dial up to turn the TV up, to have it produce more sound. The main thing an AC produces is cold air, so you turn it up to produce more of it.
You turn the thermostat down to turn the AC up.
Our office air con has 3 temp settings - hot, fan only, and cold. If I want it cooler, I’d say “turn up the AC”. If I want it warmer, I’d say “turn up the heater” . Referring to “The AC” refers to turning up the fan, with the temp dial on cold, referring to “the heater” refers to the exact same machine, but with the temp dial on warm. We almost never use *just *the fan for some reason.
https://boards.straightdope.com/sdmb/showthread.php?t=728300&highlight=conditioner
I’m jealous you have more responses, but the results seem consistent/
Now to solve the problem of the past tense of “blow dry”