SQ = hot, but when I asked they turned it down.
LH = hot , but I had the sense that they were only following rules.

UA = OK for me.

I found the upper deck to be on the warm side.

In my limited sample of AirAsia flights, they keep the cabin temperate at arctic. I was freezing on my red eye HND-KUL. Only had a lightweight sarong as a blanket which barely helped and I was too cheap to buy a blanket. I generally like it cold but this was ridiculous :(

I vaguely recall some MH flights being rather chilly which matches up my general experience with AC temperatures in Malaysia. Felt kind of silly when I started taking a jacket with me for general sightseeing even on hot days but was absolutely necessary to not freeze indoors!

This is a BIG pet peeve of mine. If people are chilly, they can use the blanket or put on a sweater. If the cabin is too hot and, as is often the case on longhaul J/F, there's no individual air nozzle above the seat, what are we to do?

Unless you measure with a thermometer any opinion of hot/cold is just a personnel perception.
Air flow on the head greatly effects the perception of hot or cold.
Humidity also effects the perception, but aircraft have a low absolute humidity. (Relative humidity is a different measurement)
22°C / 72°F is the normal setting for office air conditioning (in my part of the world)

I wholeheartedly agree with this.

I recently flew long-haul LH segments in the A340 and 748, and both were ridiculously hot. My whole body was wet with sweat. In every case I asked the FAs if they could lower the temperature. It made buying a J ticket useless because I was unable to sleep.

Another flight that comes to mind was a 764 run on UA. Same story -- so hot that I couldn't sleep in my J seat. I asked the inflight service manager to lower the temp, but it never got cool enough to sleep.

I used to frequently fly QR ultra long hauls, and I never remember having problems with the temperature aboard those flights. It's tempting to travel with a portable thermometer just to prove I'm not insane!!

In indoor, non-breezy environments such as offices and aircraft, I will generally perceive it as too hot at about 24.5-25°C. While aircraft have low humidity, the lack of airflow and the effects of eating and drinking tend to compensate. Like you, I'm used to 22°C as office temperature, which makes the majority of aircraft feel slightly warm.

I will always take too cold over too hot on a plane, but I am usually ok. The only recent flights that stand out to me were:

1. Austrian Toronto - Vienna last year, I was in the emergency exit economy row, and it was so cold they actually provided duvets (not the blankets the rest of the cabin had) to compensate.

2. Air Canada Toronto - Haneda a couple of years ago, it was ridiculously warm, in part, I think, because there were no real window shades (it was a dreamliner). The sun was beating down on the left hand side of the plane, I was on the right so although warmer, I was ok, but those on the left by the windows were not happy campers

3. Westjet Cancun - Toronto last year, it was stonkingly warm, and the woman in front of me asked the flight attendant if she could make the cabin a bit warmer because she was cold - she was in teeny shorts and a boob tube!

Always found SQ to be a heatwave. Just had another hot flight but also had a SIN to Hong Kong and it was freezing. I had to cover myself with 2 blankets

Aren't there specific rows on the UD known to be hot? I flew SFO-HKG in Row 16 and was okay but I want to say 1-2 rows behind me was pretty warm...enough that the flight attendants remarked about it.

The rest of UA and AA are generally comfortable for me. On the cool side.

I only ever tend to run into exceedingly cold cabins. Good to know the opposite is a possibility too, and glad to have avoided it thus far.

I understand that not warming up the air beyond the bare minimum is a cost-saving measure. If cabin air is too hot then, would it mean that too much of it is being recirculated? Is there a lower limit (regulatory or otherwise) on how much % of the cabin air must come from the outside, or can the fresh air intake be set to 0 for the whole duration of a 10h+ flight?

I have only flown Delta (PM NWA) and Korean Air to Asia. Korean does not have air vents so I was not comfortable on the trip. I need air flowing across my body to feel cool and the personal air vents do the trick. I have since bought a small battery operated fan to use on these trips.

My wife is from a tropical country, so she likes it warm. I on the other hand prefer the cooler temperatures. I also have heard from so called experts that we tend to get better sleep in a cooler environment. The body's blood flow and "cooling" system doesn't have to work so hard so more systems shut down so you can rest easier.

That is not true.

The air comes off the engine in the 400-500 degree range and must be cooled before it enters the cabin. How much it is cooled does not have a noticeable effect on fuel use.

http://aviation.stackexchange.com/qu...rcial-airliner

I've been in Europe for most of the past month, and it is hot everywhere. Europeans love heat, and have no desire to allow any cold air into their buildings. Even when the temperature outside drops to say 55 degrees overnight, my unairconditioned rooms have been misery. Having the window open is not enough without air circulation.

I looked on Amazon and they make a 10-inch fan with a re-chargeable battery. I do not plan to go to Europe again without one to at least stick in the hotel window to try to bring in a little bit of cold air. In addition, I figure I can put it into my backpack/computer-bag and use it on the plane if it is too hot, which is about 80 percent of the time.

Here are the average temps (avg./avg. min/avg. max) on my flights since 2002 in °C:

CX: 22.5 21.1 23.9
LH: 23.0 21.9 24.0
AC: 23.2 21.7 24.6
UA: 23.3 22.2 24.3
TT: 23.4 22.9 24.0
VA: 23.4 22.6 24.2
AS: 23.6 22.8 24.4
AA: 23.7 22.7 24.7
QF: 23.8 22.9 24.8
DL: 23.9 22.7 25.2
SK: 24.1 22.5 25.7
TG: 24.2 23.3 25.1
WN: 24.3 23.3 25.2
MH: 24.4 23.6 25.1
SQ: 24.6 23.0 26.1
NH: 25.0 23.8 26.2

This excludes airlines I've only flown on once or twice.
The averages of the min and max temps for each flight obviously don't differentiate between the cabin temp being unusually extreme for just a short period or for 10 hours. (e.g. I find TG to be ok, but its figures are inflated because BKK is always hot and it takes time for the plane to cool down. Similarly, I've only ever flown WN in summer.)

I love CX, but find all the airlines from CX to TG to be acceptable most of the time. NH is horrendous.