Originally Posted by
Airjosh
Talking with the Captain (Captain Bob) on flight 912, ms. Xix, she explained that on the triple class 757-200 plains the coach section is always warm and customers often complain. She hypothesized that it may have something to do with how they converted the airships from two class service to three. After seeing the Mickey mouse way they put together the first and business class galleys, it makes sense that balancing the cabin HVAC service might have also been less then well thought through.
While I've been fortunate enough to avoid Y on this route, this explanation makes sense to me. C is often very very cold on these flights immediately after take-off, and almost without exception FA call buttons are pushed and I hear passengers requesting that the cabin temperature be turned up. This usually results in some heat blowing in the cabin and a comfortable short-sleeve temperature in C.
I would suspect that if the same temperature air is being blown out of the vents in C and Y, that Y will be uncomfortably hot given the higher body heat load from the much higher passenger density in that cabin. Y probably needs cooling while C needs heating, but it doesn't seem like that's possible, and as others have pointed out, the FAs seem to be inclined to listen to the "it's too cold crowd" and turn up the heat.