You must make sure that he owns a valid license from the Régie du bâtiment du Québec (8 or 10-digits RBQ number) with the sub-category corresponding with the type of fuel you chose (10 for wood-pellets, 15.2 for natural gas or 15.6 for propane). To check whether a contractor has the correct license sub-category, consult the Registre des détenteurs de licence RBQ.