Yes, Coleman is quieter than a Domedic. THe eastest thing to do since you are not experienced is to install a unit with the controls on the face of the unit. No t-stat wires and t-stat to install. Also a non ducted unit as you are just trying to do the bed room. Again less work. Just remove the vent and place the unit over the hole. Grab a six pack and watch lots of you tube to see how it is done. You will have to get very creative as to how to get the unit one the roof. Fork lift, tractor with front bucket, 3 people with lots of rope and ladders. Near by tree and a block and tackle. Think outside the box.