Start by deciding whether you want an audio-only monitor or one that lets you see as well as hear your baby. Some parents are reassured by hearing and seeing every whimper and movement. Others find such close surveillance to be nerve-racking. Having a monitor should make life easier, not create a constant source of worry. You might find that you don't really need a monitor at all, especially if your home is small.
A baby monitor, also known as a baby alarm, is a radio system used to remotely listen to sounds made by an infant. An audio monitor consists of a transmitter unit, equipped with a microphone, placed near to the child. It transmits the sounds by radio waves to a receiver unit with a speaker carried by, or near to, the person caring for the infant. Some baby monitors provide two-way communication which allows the parent to speak back to the baby (parent talk-back). Some allow music to be played to the child. A monitor with a video camera and receiver is often called a baby cam.
Some audio/video monitors filter out "normal" sounds and motions. The receiver is supposed to turn on only when your baby makes an unusual motion or sound, such as crying or rolling over when he's waking up from a nap. This feature is designed to extend battery life, although the receiver should be docked for overnight monitoring to keep the battery charged. We haven't tested any models with this feature, so we don't know how well it works.
Security is a mixed bag, especially as baby monitors get more high tech. If tech giants like Apple and Google run into security flaws, high-tech baby monitors are sure to experience similar problems. However, some less high-tech baby monitors aren't secure, either, and many suffer from signal interference. We've checked each company's security policy to find the most secure options for you.
If you aren't interested in having a video baby monitor, the VTech DM221 is the very best audio-only monitor you can buy. You can listen in on your baby or get vibration and light-based alerts when the monitor is in silent mode. The five LED lights indicate the level of sound so you can tell whether your baby is cooing quietly or shrieking for mom and dad.