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Visited NYC several times. Metro was unbearable in summer because trains heated up outside and blasted the warm air into tunnels and stations through AC.

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AC doesn't really create heat though, aside from minor amounts from the compressor/fan motors, it merely moves it from inside to outside, or into the metro stations as you mention.

Yes, AC moves heat from inside homes outside into the city.

My point is that it doesn't create heat, thus does not contribute to climate change on its own. Only the energy source that powers it potentially does.

Since ACs are pretty far from 100% efficient, they turn electricity into heat. There's also heat generated along with the electricity because generation isn't perfect either.

The HVAC fan alone in a surban house can draw 1KW. That’s pretty much all heat.

The AC cools the house at the cost of many more KW.

The house gets cooler but this is all heat from the electrical usage.

To put that into perspective:

The AC cools the house using about 3-4kW, total.

The roof on the house (assuming 29N because the article is about Houston, so between 10AM and 2PM, that's a Solar irradiance of 1kW/m^2) is receiving 157.9kW of sunlight, and then absorbing about 85% of that.

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