For audio/video products, this is made up of picture performance (30%), sound performance (40%) and ease of use (30%). For audio-only products, the overall score is made up of sound performance (70%) and ease of use (30%).
We test how well the baby unit can pick up soft sounds, how well the carer unit can reproduce that sound, signal range and performance through walls. Results may vary depending on your home Wi-Fi coverage. For app-based products, we define the carer unit as the tablet/phone.
We look at ease of using the controls on both baby and carer unit, labelling, ease of setup including handling, positioning and adjusting settings and ease of accessing the batteries and connecting the adaptors. For apps we class the tablet/phone as carer unit.
Some baby monitors sound an alarm if the temperature is outside a certain range. (Regardless of the temperature, it's still important to follow safe sleeping guidelines such as putting baby to bed on their back, with face uncovered and minimal bedding.)