This depends on the model you buy. There are some toothbrush sanitizers that can be highly effective at cleaning your brushes but may be a little noisy in use, making a kind of humming or vibrating noise. This can be bothersome to some people, especially if you want to sanitize your toothbrush early in the morning or late at night and don't want to bother people who may be trying to sleep nearby. In most cases, however, like with the MECO Toothbrush Holder, you won't need to worry about too much noise at all when using these devices.