Should I need the air duct cleaning license or some license like that to stard the air duct cleaning business? -

Oh man - in California they probably require a license and insurance for everything. One good area to get into is asbestos abatement - you ll run into asbestos a lot while cleaning ducts - and if you could THEN be the guy who cleaned this stuff out, you d be in the chips.You d probably need a separate license for everything. Asbestos is not really a big deal except that town governments are terrified of it now - so it means a LOT of money for you to make it go away.

Every state has different laws so best you look up or ask your local council.It is recommended you contact the Institute Of Inspection cleaning and Restoration Certification and do a course with them.Most of their courses are relatively cheap and you will learn a lot.This certification can also aid in you obtaining new business.Good luck.