What to Expect from Video DoorbellsBattery vs. WiredMost smart doorbells replace your home's existing doorbell, so you can expect them to have similar power requirements. This means your doorbell needs 12 to 36 volts of AC electricity to run properly. If your home doesn't meet these requirements, you or an electrician may need to install a new doorbell transformer. While we found battery powered units such as RemoBell quicker to install, doorbells like the Ring Video Doorbell 2 that also connect to your existing doorbell wiring are superior in almost every way. However, batteries mean units are much larger than a traditional doorbell button. In contrast, doorbells that only use a hardwired connection, like the Nest Hello and Ring Video Doorbell Pro, are slimmer and usually look nicer. ChimesAlthough video doorbells replace the button on your doorbell, some still need the chime already installed in your home. There are two types of doorbell chimes on the market: mechanical and digital. A Ring spokesperson said the main difference is that "Mechanical doorbells make your generic "ding dong" sound, whereas a digital doorbell has a speaker, and can make various sounds, including playing MP3’s and pre recorded sounds. Having one chime or the other does not affect doorbell performance, so it’s ultimately user preference.