Over the scale of an entire city, it might be negligable, I don't know, I haven't done the math. My guess would be it is measurable, but not a lot, probably less than a degree. But the GP said "no it doesn't" increase heat. I'm just saying that even if it is a very small amount, it does increase heat.
And if you stand near an AC unit, you can definitely feel heat coming from it.
And if you stand near an AC unit, you can definitely feel heat coming from it.