Sefuthumatsi sa khase ea air duct flue ke sesebelisoa se sebelisoang ka ho khetheha ho futhumatsa le ho alafa khase ea air duct flue. Hangata e na le lisebelisoa tsa ho futhumatsa, lisebelisoa tsa taolo le likhetla, joalo-joalo, 'me e ka sebelisoa haholo liboping tse fapaneng tsa indasteri, licheso, lifemeng tsa motlakase le libakeng tse ling moo khase ea flue e hlokang ho ntšoa teng. Ka ho futhumatsa khase ea flue mochesong o itseng, lintho tse kotsi tse kang mongobo, sulfide le nitrogen oxides ka khase ea flue li ka tlosoa ka katleho ho hloekisa moea le ho fokotsa tšilafalo.