Works straight out of box, can have running in 5 mins. Attach the pipes and off you go. I use in my camper trailer which has canvas sides and it adds about 7c on low. Low is the only way to use it as it's quiet and uses less fuel, runs for about 17 hours. When on high it chews the juice at a much higher rate than advertised anyway. Clock and timer function are frustrating to operate and takes some time to figure out the method to set. Timer always means it kicks off at max temp too. Otherwise I'm happy with it, puts a nice heat in the camper and as drawing air from outside it turns the air in the camper over which is nice to sleep in.