Phone coolers work, but most users don't need one, Engadget finds
Active phone coolers do lower temperatures and can stop a phone from throttling, but according to Engadget, most people never push their devices hard enough or long enough to justify buying one.
The products sold as phone coolers differ widely. Basic models blow air across the back of the handset. Thermoelectric, or Peltier, coolers pull heat away through a cold plate. Passive cooling cases spread heat over a larger area. So-called cooling apps can reduce workloads or change performance settings, but they cannot remove heat from the hardware itself.
The question that matters is whether heat is actually dragging down performance. A phone's CPU and GPU generate substantial heat under load, and when the device gets too hot it throttles to protect itself. The effect shows up in a game that runs smoothly at first and then slows as the phone warms.
External cooling can measurably change that. Notebookcheck recorded 3DMark stability scores of 77 percent and 79.2 percent on the ASUS ROG Phone 8 Pro without the AeroActive Cooler X attached, compared with 92.7 percent and 90.8 percent with the cooler in place. Higher percentages indicate steadier frame rates as the device heats up.
A cooler therefore helps with lag only when heat is the cause. It will not fix weak Wi-Fi, server lag caused by distance, or a game the phone cannot run well in the first place.
The clearest case for a dedicated cooler is long gaming sessions, particularly when performance drops after the phone has been under heavy load for a while. Livestreaming, video processing, extended outdoor photography in summer and other sustained workloads raise the same problem. Cars are another setting: navigation, high screen brightness, charging and direct sunlight can combine into exactly the kind of heat an active cooler is meant to counter.
Before buying one, Engadget suggests simpler fixes. Positioning the phone near an air-conditioning vent, assuming the ambient temperature allows it, and mounting it where cool air can circulate may solve the problem without adding a powered accessory to the dashboard. Removing a thick case, keeping the phone out of direct sunlight and avoiding demanding tasks while charging also help.
Gaming while charging deserves separate attention because charging produces extra heat. Wireless charging should be avoided in that situation, since it runs hotter than a cable. Some Galaxy phones offer an option to pause USB PD charging during gaming, which lets compatible hardware power the device without continuously charging the battery.
Engadget's conclusion is that a dedicated phone cooler makes sense when a phone repeatedly throttles during extended workloads and the simple measures fail. Otherwise the buyer is adding weight, fan noise, likely another cable and possibly something that interferes with their grip, all to make the back of the phone colder.