We performed experiments to compare the efficacy of disinfectants and plasma on biofilms of the bacterial strains E. coli K12 and E. faecalis Symbioflor® grown for 20 h. The disinfecting agents aqueous ethanol (70%), peracetic acid (PAA) (15%), and sodium hypochlorite (NaOCl) (3%) were used and compared with an atmospheric plasma jet. Sterile Mueller-Hinton-1 (MH1) growth medium and deionized (DI) water were used as negative controls to replace the bacterial suspension and/or the disinfectant agent. A thermal biofilm sensor was used to detect not only the effectiveness of chemical substances versus the plasma jet in removing biofilm but also possible growth after treatment. The biofilm was grown for 20 h and the different disinfection methods were then applied. The plasma jet and the NaOCl were the most effective treatments and while the plasma jets effect can be instantly switched on and off, NaOCl is a liquid solution that exerts its effect as long as it remains in place.