If it is a Generac/Guardian system, the typical pre- packaged system takes about 3-4 hrs to do. Make sure to put the generator 3 ft. from any combustible materials( like the house). also, should try to get as close as possible to the main panel. the genarator requires 11-14" water column pressure, NG or LPG. this usually requires a seperate regulator. If you postion the unit right, there is little in extra material to get. An annual maintenence agreement is a great way to make additional revenue from generator sales. Look at around 1-2 hrs(depending on liquid or air cooled) for annual maintainence.
