look at the little delongie [mind the spelling]there small quite and economical,theese things have been part of my job for 20 years and i personaly think there brilliant,thats all makes,used to be the ebac repair engineer asswell.even the big ones only use the same compressor as a chest freezer,the small ones same as a fridge.often blamed for useing a lot of eletric but there not that bad at all.i run one on a timer for 12hrs a day in the garage to keep the car right.

try running it downstairs flat out for the first week to dry the house out,it often sorts the upstairs out asswell without the background noise.