IMPORTANT: Professional installation is recommended, since this unit doesn't come with a transformer and power cord. It only comes with a electric cable in order to be connected directly to a 24 volts source. - - PHI Technology (Photohydroionization) creates a group of "Friendly Oxidizers" (Super Oxide Ions, Hydro-Peroxides, Hydroxides.) Oxidizers revert back into O2 and H2O. Oxidizers are extremely effective at destroying microbes and gases. All of the oxidizers created exist in outside air already. It doesn't harm people.