alt Hacker News>And it raises the heat outside of buildings.
No it doesn't. Seriously, where does this meme even come from? It should be pretty obvious just from a solar insolation map that AC is just noise vs the sun. The energy usage is tiny vs vehicles or non-heat pump heating and only electric. What changes temperature overall is the balance of thermal retention by the atmosphere vs radiation into space, hence why net increases in GHG are so dangerous. And at the ground level similarly how heat is dumped to atmosphere. Greenery, whites, shade etc is good, asphalt, mass standard glass is bad (hence many cities being heat islands). Old, leaky units sure, we absolutely should work to reduce that. But it's astonishing how people claim AC makes the outdoors hotter so consistently.
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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.
> No it doesn't.
Yes, it does. It may be small temperature increase but AC use increases outside temperatures. It is just physics.
Here is a simple diagram: https://www.lozierheatingcooling.com/filesimages/heatPump.jp...
This simulation claims otherwise (though I agree it's hard to believe):
> A significant degradation of external thermal comfort can also be seen in the simulations, as heat released by AC systems warms the outside air (see figure 3). The temperature increases due to AC depend on the time of day and on the characteristics of the heat wave, mainly its intensity. On average, the duration spent under high heat stress conditions in the streets is increased by about 20 min per day because of AC.
https://iopscience.iop.org/article/10.1088/1748-9326/ab6a24#...