I've done it lots of times especially when the kids had colds, flu etc. It definitely seemed to kick out the bugs. We use a cold humidifier rather than one that produces steam because the heat will destroy the H2O2 (Hydrogen-Peroxid) nascent oxygen. I think I've even used more than that, maybe up to 2 oz. I just do a free-pour of H2O2 (Hydrogen-Peroxid) into the water. Nothing too scientific.