If it is a replacement and is of the same type then it is easy,but. First will a competant person fit it.If you know what you are doing then connecting up the wiring should not take longer that 10 min' and connecting up gas say 5 min' ,screw on any deflector plate another few min' pushing back into place couple of min', replacing screws through sides few min'. Then test for all supplies.Some people make it sound like rocket science but it is not , long as you are qualified to do it that is.However if it is a special then many factors have to be put into place.