Moderator, Iberia Airlines, Airport Lounges, and Ambassador, British Airways Executive Club
Join Date: Feb 2010
Programs: BA Lifetime Gold; Flying Blue Life Platinum; LH Sen.; Hilton Diamond; Kemal Kebabs Prized Customer
Posts: 63,761
Twenty celsius for me is perfect, if a little warm. Current temperature in this Northumberland house (no central heating): 17.6c. We just need to invent some farm animal which grows a warming offcut product, suitable for clothing, in return for eating grass. It's so individual that there isn't a right or wrong about it, however pressurisation seems to add a dimension to it, cold dry air really getting to some people. Best to have the aircraft cool so you add clothing, rather than hot since you really don't want the reverse.
Oh and never believe an aircraft thermostat!