Originally Posted by
nzkarit
The cost the sky couch if brought is roughly inline with buying the three seats. Maybe some differences as there isn't the mass of a person and the baggage they carry. Plus no meal. And need less AC as less people releaseing body heat, so can run the engines at a lower thrust setting. That might not be much but for 12 hours it all adds up. It is basically getting people to pay for seats and never have people sit in them.
This inconsequential in my view. Remember it is -50 C outside at typical cruising levels for long haul flights, so the the aircraft is heating and cleaning the air that it circulates.