EZSMART Corporation, ESA/ECRA #7012690 , North York , Ontario
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Charging a phone on a bed is a widely practiced habit — and a consistently dangerous one. The combination of a heat-generating device, a thermally insulating surface, and a user who is often asleep creates the conditions for a phone fire with no one awake to respond to it. The Electrical Safety Authority (ESA) in Ontario identifies overnight phone charging in bed as a recognized fire hazard, particularly in combination with certain charger types and phone models.
No. Charging a phone directly on a bed — particularly overnight, and particularly under a pillow or blanket — is not safe. The risk is not theoretical: Canada and other countries record phone charging fires and burn injuries every year, and the causal mechanism is well established. Understanding why this happens and what the safe alternatives are takes less than five minutes.
All lithium-ion batteries generate heat during the charging cycle. The charging process involves electrochemical reactions that are exothermic — they release energy as heat as a byproduct of moving lithium ions between the battery’s anode and cathode. This is normal, expected, and managed by thermal controls built into the battery management system (BMS) of the phone. The BMS slows charging or stops it when the battery reaches a temperature threshold.
The problem is that these thermal controls are designed to work in open air. When a phone is placed on a bed — particularly on or under fabric — the heat the phone generates cannot dissipate efficiently. The phone’s surface temperature rises, the battery management system responds by slowing the charge rate, but the fabric continues to act as an insulating layer. In extreme cases, particularly with counterfeit or damaged chargers that do not regulate current properly, this can result in thermal runaway — a self-reinforcing overheating cycle that can cause the battery to swell, rupture, and in rare cases ignite.
Charging under a pillow is significantly more dangerous than charging on top of bedding. A phone under a pillow has essentially no airflow and is surrounded on multiple sides by thermally insulating material. The phone’s temperature can reach levels that char the pillow filling — foam and down are both flammable — before the user wakes to notice. Emergency response agencies in Ontario and across Canada have documented fires that began with a phone charging under a pillow overnight.
The reason people charge under pillows is typically to muffle notification sounds or to keep the phone within reach. Neither justifies the fire risk, and both are solved by simply turning the phone face-down on a hard surface away from the bed.
The Electrical Safety Authority (ESA) includes phone and device charging habits in its residential fire safety guidance. The ESA’s recommendations are consistent with those from the Ontario Fire Marshal and the National Fire Protection Association (NFPA): charge devices on hard, flat, non-flammable surfaces, never on bedding or upholstered furniture, and do not charge devices overnight unless a proper charging station or dock keeps the device elevated and ventilated.
The ESA also specifically warns against using counterfeit or uncertified chargers. In Canada, chargers should carry CSA or UL certification. Uncertified chargers — widely available through online marketplaces at low prices — often lack the voltage and current regulation of certified devices. An uncertified charger can deliver more current than the battery management system expects, accelerating heat generation and increasing the risk of thermal runaway.
Counterfeit and uncertified USB chargers present a higher fire risk than OEM chargers for two specific reasons: inadequate isolation between the primary (mains voltage) and secondary (USB output) sides of the charger, and poor current regulation. Inadequate isolation means that a charger fault can expose the phone — and the user — to mains voltage. Poor current regulation means the charger may deliver more power than the battery management system can safely handle, particularly as the battery ages and its impedance characteristics change.
The risk is compounded when an uncertified charger is used in a bed. The thermal management failure and the current regulation failure can occur simultaneously, and the insulating bedding prevents heat dissipation. Always use the charger supplied with the device or a replacement from a reputable manufacturer carrying CSA certification.
Yes. The same thermal management concerns apply to any lithium-ion device charged on soft surfaces. Laptops are particularly high-risk because they generate significantly more heat than phones and often have bottom-mounted cooling vents that are blocked completely when the device sits on a bed. A laptop on a bed for several hours will reach temperatures that can char fabric and, in some cases, cause the battery to fail. Charge laptops on hard flat surfaces and never leave them running on bedding for extended periods.
Phone and laptop charging fires in bedrooms often involve the outlet or extension cord used for charging, not just the device. If you have noticed that a phone charger or power adapter consistently runs very warm or hot at the plug end, that may indicate a problem with the outlet or circuit, not just the charger. An outlet that runs warm under low load should be inspected by an ESA-licensed electrician. See our guide on why an electrical cord might be hot to the touch for the failure modes that explain this — the same mechanisms apply to charger cables. Also see our guide on whether power surges can destroy appliances — voltage surges that come through unprotected bedroom outlets can damage charging electronics and battery management systems.
We are called to investigate bedroom fires more often than people expect, and in a significant proportion of those cases, the fire originated from a device charging on or in bed. What strikes us every time is how preventable this is — the solution is simply to move the charger to a hard surface away from the bed. We also regularly find that bedroom outlets in older homes are on shared circuits with high-draw devices in adjacent rooms, which means voltage fluctuations are more common. If your phone charger or laptop adapter runs unusually warm at the plug end, have the bedroom circuit inspected. A dedicated circuit for bedroom electronics is a modest upgrade that removes one more risk factor from an already risk-prone charging habit.
Concerned about your bedroom outlets or charging circuit? Our ESA-certified electricians serve the GTA. Call us at 416-838-9006 or visit our contact page — we will get back to you the same day.
Electrician Since 2008 Journeyman Electrician Designated Master Electrician at EZSMART Corp
