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.

The house being cooled by aircon is within the same world as everything else is.

This doesn't mean that there's zero heat added locally (as many seem fond of suggesting): The compressors and circulation blowers and fans don't run for free, and every Joule of electricity they consume is ultimately converted to a Joule of heat in a process that wouldn't occur in the absence of aircon. That's not zero.

But in very broad strokes, it's not very significant. It's somewhat akin to running a refrigerator inside of a kitchen.

With aircon, the refrigerator is the size a whole house. That certainly sounds huge, and it is huge. But that refrigerated building is inside of a room that is the size of the Earth's atmosphere, which is very obviously vast in ways that kitchens simply are not.

It doesn't really matter. Millions of homes with aircon don't mean much when the atmosphere is millions of times bigger than they are.

Eventually radiates out into space ;-) It doesn’t disappear, but we don’t need to care much about infrared passing Alpha Centauri.

Air conditioners don't need to use fossil fuels. Solar power and AC work really well together because peak solar energy is exactly when you need AC the most.

No heat is created either, that would explicitly violate the first law of thermodynamics. An air conditioner powered by solar energy (or anything solar powered) ends up releasing the exact same amount of "excess" heat as the sunlight would have if it hadn't been absorbed by the panels.

> I’m just saying air-conditioning increases climate change because it uses fossil fuels

It would actually be a much better global warming mitigation strategy to install bidirectional heat pumps (A/C in the summer, heat in the winter) that runs on electricity (which is increasingly produced using renewables) and then get rid of fossil-fuel burning furnaces.

8 billion people running a 2000 watt AC continuously for 8 hours a day = 5 trillion watts of heat. (Only the electricity consumed by the AC is turned into new heat. The heat from inside the house would have moved outside anyway, at the same rate, since it's an equilibrium)

The sun = 175 quadrillion watts of heat.

So I would say, the heat from running ACs is not significant. It's also additive with all the other existing forms of energy use we have. Unlike greenhouse gases, which are multiplicative.

It is worth noting that if the Air Conditioner is powered by electricity that came from solar panels, the net heat produced compared to letting the sun heat solar panel colored ground is exactly 0.

Air Conditioners do not produce a net heating effect unless you power them by burning fossil fuels.

When you enact 0.1% changes through a population, that's still a 0.1% change.

"If we all do this little thing" thinking is utter nonsense. If all of human consumption or contribution to warming or what-have-you is 1000, applying a change that lowers that to 999 is not doing anything more than that.

This here is not even a 0.1% thing. You could probably get a better result by telling people to read ebooks rather than hardback. It's just absurd.