I don't know why dual pipe portables aren't more widely available. The common single pipe versions pump all the hot air outside, but they draw an equal amount of warmer air in from elsewhere, ruining their efficiency. They do cool the room to a certain extent and provide some nice cold airflow. But splits are so much more efficient it's crazy, they probably pay for themselves vs a portable over their lifetime of equal usage. My two splits use 3 to 4.5KWh on the hotter days with both units running all day, keeping the bedroom at 18ºC and the living room at 20-21C, combine that with the average unit cost of Octopus Agile, it's costing £1/day at the upper end to live in a very comfortable house. Pair that with other benefits such as not having the windows open and letting all the flies in, or the smells of nearby BBQs etc, it's a win.
