Microphone sensitivity: There’s a difference between hearing your baby cry, and hearing every little noise. All baby monitors have the option to turn down the volume, but some offer thresholds for parents who are more comfortable with only hearing the biggest upsets, and prefer not to hear the self-comforting noises their baby makes as they fall asleep.
The Infant Optics’s range within our test houses was never an issue, and, as with others we tested, we had to walk outside and down the street before losing the signal. The image quality was good enough to make out facial details 6 feet away in a completely dark room (as it was on others we tested). It’s easy to add more cameras to the set (you can use up to four Infant Optics add-on cameras, which are separate purchases, usually for about $100). You can mount the camera on a wall easily, pan and tilt 270 and 120 degrees respectively, and you can set the parent unit to scan between multiple cameras to keep an eye or ear on everybody at once—another nice feature that’s not unique to this model.
This video baby monitor streams real-time footage to a 3.5" color display without connecting to the internet. The product’s battery will last around six hours if the display is always on but can last up to 10 on standby, and it’s range is up to 700 feet, though parents note it doesn’t reliably transmit a signal through numerous walls. In addition to providing high-quality video, the camera has an alarm function, two-way talk, a temperature monitor, and night vision. You can remotely adjust the camera’s angle or zoom with the controller, and if you want to use it as a regular baby monitor, you can turn off the video function.
The best monitor for sound in our tests is the Philips Avent SCD630, with a score of 8 of 10. This monitor has the best sound activation and background cancellation features in the group, and while the sound is bright, it is also clear without an echo. Most of the competition earned 4s and 5s for sound, with all of the Wi-Fi monitors only earning 4s. It seems that no matter how good your parent device might be, the Wi-Fi cameras struggle for the most part to transmit clear sound with good sound features.
While buying an audio-only monitor in 2018 is slightly akin to buying a flip phone, the Philips Avent has pretty much all the same features as top-of-the-line camera baby monitors, sans camera. Even better, it uses DECT (Digital Enhanced Cordless Communications) technology to guarantee zero interference ⏤ so it won’t get crossed with other signals in your house and/or your neighbor’s cordless phone. The Philips has a range of more than 90-ft inside, a 10-hour battery life, and it uses a “cry mode” so you’re only alerted to real cries for attention rather than background noise. As for extra features, it includes a night light, in-room temperature monitor, and plays lullabies ⏤ if only you could just see the baby.
The VTech DM221 audio monitor is the best choice in the category—it's consistently a best seller at multiple retailers, with thousands of positive customer reviews. Losing video is a major sacrifice, of course, but we could see this monitor being a good choice for parents of toddlers who are considering replacing a failing monitor, or people who want a monitor only so they can hear their kid crying out from a distant bedroom.
Wireless encryption: This ensures that no one else can tap into your monitor’s “feed” and see what’s going on in your house. WiFi-enabled monitors are great for portability and range, but may be more susceptible to hacking. If you go this route, be sure to secure your home wireless network and keep the monitor’s firmware updated. Otherwise look for digital monitors with a 2.4 GHz FHSS wireless transmission.