Wired has reviewed the Coway Airmega Halo, a new mid-size air purifier released at the end of August that aims to offer affordable, whole-room air purification with a particular focus on quiet, sleep-friendly operation. It sits within Coway's established Airmega line, which has long been a favourite in Wired's buying guides, between the compact 50/100 models and the higher-capacity 350/450 units. The reviewer found the device largely delivered on its promises but flagged concerns over its sensor accuracy and a lack of transparency in reporting pollutant levels, alongside some usability drawbacks.

At just 9.7 pounds, the Halo is lightweight and easy to place thanks to its cylindrical, 360-degree air-intake design, though it lacks a handle or wheels, making it awkward to carry for users with limited grip. Inside sits a three-stage, IEST-certified HEPA filter claimed to capture 99.97% of particles down to 0.3 microns, paired with a MegaScan sensor that tracks smoke, dust and allergens down to PM2.5 level. Unlike some rivals, it has no app, remote or Wi-Fi connectivity, and displays air quality via coloured lights rather than precise figures. On its quietest sleep setting, the reviewer's decibel meter could not detect any fan noise above ambient household sound, close to Coway's stated 17-decibel claim.