[thayne]

The way AC works is by transferring heat from one place (inside) to somewhere else (outside), and it takes energy to do this which produces even more heat, which is generally in the outside part of the AC system. This isn't something you can engineer away either, it's a result of the second law of thermodynamics.

Is that increase small compared to other things, like surfaces that absorb more solar radiation? Maybe. It depends on a lot of factors, but the amount it increases the heat of the outside is certainly non-zero.

[PowerElectronix]

The difference in ambient temperature due to air conditioning pumping heat outside is unmeasurably low. If all the power a city uses went to AC, it'd still be negligible compared with the sun irradiation on its surface.

[toasty228]

1c to 2c according to simulation in Paris, even up to 3-4c for some streets

The exhaust of a single car/plane/ship are also immeasurable, yet here we are...

[thayne]

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.

[gsquaredxc]

You can reason it out (in a way that might make Fermi proud) pretty easily: a very large AC unit can be powered by a very small (relative) solar panel, where the solar panel is maybe 20% efficient. Thus, solar irradiation is substantially higher than AC power usage.

[vanviegen]

That's only accounting for the energy the airco unit consumes. What the airco unit does is remove heat from the inside of the house, and dump it outside. That effect is about 4 times larger.