A co-worker of mine and his wife adopted a baby from China, he said when he and other western people went there, and occasional trips back there, they were shocked at the heat!
Not the outside temperature but inside he said anywhere they went whether inside a bus or a hotel it was boiling hot all the time, thermostats set at 25C or even 30C!
Uh!? Your friend probably hasn't been to southern China. Heating is rather uncommon in Guangdong or Guangxi for example, even inside apartments or restaurants. I recently traveled to Guilin (Guangxi) and usually had to keep my winter jacket on when eating in restaurants. My Shenzhen apartment doesn't have heating as well so when it gets close to 0, better have warm clothes.
I figured it would be the other way around people in the south art of China, which I think is where my co-worker went, would be hot so people would be accustomed to heat.
My cousin married a guy from Australia and it was funny to see the reaction to certain temperatures. My cousin is used to winters here which get to about -25C but in Australia (Canberra I think it was) she said people wore winter coats when it was +20C, to them it was bitterly cold she said.
It makes sense that you acclimatize to a warm climate I wish I could live someplace warm :(
Not the outside temperature but inside he said anywhere they went whether inside a bus or a hotel it was boiling hot all the time, thermostats set at 25C or even 30C!