How far away baby's monitor can be from the parent unit is what determines a product's range. While many manufacturers offer a "line of sight" range to describe a monitor's range, it is not a good indication of how well it will work in your home with walls and interference. It doesn't matter how much you like a specific model or brand, if it doesn't work in your house, it simply isn't going to work. We tested both indoor range and open field tests to provide the best information, but remember that the values inside your home matter more than those in an open field, unless of course, you are leaving a baby alone in an open field (which we don't recommend).
It may surprise you to hear that simply being able to last through the night, unplugged, with the display off, qualifies as exceptional battery life for a baby monitor. The Infant Optics was one of the only monitors in our testing that could easily do that, and then last a while longer the next day before needing a charge. (The manufacturer claims it lasts 10 hours with the display off—we got that amount of time off a full charge, even when checking the display intermittently.) This model also charges via a USB connection, which actually sets it apart from a variety of competitors, some of which use ineffective and inconvenient proprietary DC chargers or even disposable batteries.
Parents are spoiled for choice nowadays, thanks to the rise of the connected home and new technologies like live-streaming video and high-resolution cameras. No matter which type of baby monitor you buy — whether it be an old-school audio-only monitor or a fancy Wi-Fi video monitor — it will have two parts: a monitor in the baby's room and a receiver that you carry around with you to hear and/or view your baby.
Sound devices relay what is happening in baby's room via sound only. A great sound option is quiet unless the baby is making noise so that you won't be disturbed by white noise or constant static. This basic monitoring type can be all you need if your goal is being alerted when your baby is crying and needs your assistance. This style can be elementary with sound only like the V-Tech DM111 or it can have bells and whistles like a nightlight, 2-way talk, lullabies, and mic sensitivity adjustment features like the Philips Avent DECT SCD570/10. Most parents can get by with a sound only device as it provides the information you need to determine if your baby needs you or not.
This monitor is known for its zoom lens, included in the box, that lets you see your baby up close even if you have to position it farther away from the crib. You can use the monitor to remotely adjust the camera, and you don’t have to worry about plugging the monitor in overnight—it can sit on your nightstand for up to 10 hours in the power-saving mode (similar to sleep mode on your computer, but it still provides sound monitoring while the display is off) and up to six hours with the display screen constantly on.