Yes, outdoors, with high humidity, and 27C can become uncomfortable. But keep indoors away from direct or indirect infra red radiation (hot surfaces in sunlight like external walls and roofs can radiate a lot of IR into windows and the like, sunlight streaming into a window can add 1KW heating per square meter of window), in humidity low enough so you don't sweat, and add a fan then as you can see from that graph (area 12) it can be pleasant up to 30C. But remove the fan, raise the humidity, and even 25C can become downright unpleasant.
Setting the air-conditioning to 27C should be comfortable in the right clothes. Provided it is significantly hotter outside, the air conditioning won't just drop the temperature to 27C, it will drop the humidity as well. Keep the air moving and your body will do the rest.
I work from home most days, living in Sweden which makes me more used to colder temps. Some weeks ago we had a few days over 27C and my working space thermometer measured 26C inside. It was perfectly comfortable.
My working space thermometer was also measuring 26C last week and I was very uncomfortable. Tolerance for warm and cold temperatures is different for everyone.
The 27C headline figure would make more sense if it was something not commonly quoted, the web bulb temperature:
https://www.researchgate.net/figure/Psychrometric-chart-Givo...
Yes, outdoors, with high humidity, and 27C can become uncomfortable. But keep indoors away from direct or indirect infra red radiation (hot surfaces in sunlight like external walls and roofs can radiate a lot of IR into windows and the like, sunlight streaming into a window can add 1KW heating per square meter of window), in humidity low enough so you don't sweat, and add a fan then as you can see from that graph (area 12) it can be pleasant up to 30C. But remove the fan, raise the humidity, and even 25C can become downright unpleasant.
Setting the air-conditioning to 27C should be comfortable in the right clothes. Provided it is significantly hotter outside, the air conditioning won't just drop the temperature to 27C, it will drop the humidity as well. Keep the air moving and your body will do the rest.