Farpoint Group found common wireless devices and equipment frequently caused interference to wireless-LAN traffic. For example, microwave ovens caused throughput reductions of 62%, Bluetooth headsets caused approximately 20% reduction in throughput and some household devices such as cordless phones caused a 100% reduction. For video, most types of interfering devices could cause pixelation and/or an unwatchable picture. As wireless LANs become the default connectivity for essentially all users in enterprise environments, interference issue will become more acute.”]
Source: https://www.darkreading.com/attacks-breaches/devices-interfere-with-wifi