January 5, 2026, 3:03 pm | Read time: 3 minutes
Many iPhone users charge their smartphones overnight to ensure enough battery life during the day or to avoid missing an alarm. However, Apple warns about the dangers posed by heat if the iPhone or charging cable is poorly ventilated or in direct contact with the body during charging.
Avoid Charging in Bed
On its support page, Apple provides an extensive list of “important safety information for the iPhone.” This includes tips on handling, repair, potential hearing damage, and charging the smartphone.
A significant portion of the safety information focuses on the correct charging of the iPhone battery. The company not only addresses when damaged chargers and cables are unsafe but also the effects of heat on the iPhone and users.
Apple generally advises against prolonged skin contact with charging cables or USB plugs that are connected to power. In the worst case, this could “lead to skin irritation and burns.” The company also warns against sleeping or sitting on cables or plugs: “For example, you should not sleep on a device, power adapter, or Qi charger, or place these devices under a blanket, pillow, or your body while they are connected to a power source.”
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Good Ventilation Ensures Safety
The problem with charging the iPhone under a blanket, pillow, or body is the heat generated. Although Apple’s chargers and cables comply with “prescribed limits for surface temperatures,” they can heat up to the point of causing skin burns when covered.
Apple points out that “the iPhone, power adapter, or wireless charger should be in a well-ventilated area during use and charging.” Special caution is advised for users with physical limitations that make it harder to perceive heat on the skin.
Fire Departments and Police Also Warn
Fire departments also point out the risks of charging overnight. In a video on TikTok, a firefighter from Kent Fire Rescue in the United Kingdom explains why overnight charging can be dangerous. The key point: Many people use cheap or defective chargers, and even original chargers have reportedly caused fires.
The local fire department in Schruns, Germany, also explicitly warns about the risks of charging in bed: “If a device is connected to the charger for an extended period, it can overheat. Especially with cheaper chargers or those without temperature control, there is a risk of overheating and, in the worst case, a fire.”
The 33rd Precinct of the NYPD has firsthand experience with what can happen if a smartphone is left under a pillow overnight. In 2016, the officers shared images on X (formerly Twitter) showing several devices that caught fire. The precinct warns that not only can charging under a pillow lead to heat buildup, but even sleeping on the pillow alone is enough if the device is underneath.