In the summer, car interiors can reach extremely high temperatures. On a 90 degree day, the interior of a parked car can climb to over 160 degrees in just half an hour! These extreme temperatures can damage electronics like cell phones, causing issues like battery swelling or premature failure. Thankfully, there are steps you can take to keep your phone safe from summer heat when it’s stored in a hot car.
Why car interiors get so hot
There are a couple key reasons why the inside of a parked car becomes a scorching hot oven in the summer:
Greenhouse effect
Sunlight enters through the car windows and gets absorbed by the seats, dashboard, etc. This interior surfaces then radiate heat in the form of infrared radiation. However, the infrared radiation cannot pass back out through the glass windows. This one-way passage of solar radiation is known as the “greenhouse effect.” The result is rapidly rising interior temperatures.
Lack of air circulation
When a car is moving, air flows in through open windows and vents. This airflow removes heat from the interior. However, in a parked car, air cannot circulate well and heat builds up inside. Cracking the windows open a bit can help increase airflow and slow the temperature rise.
How heat damages phones
Excessive heat can harm smartphones in a few key ways:
Battery swelling
Phone batteries contain lithium-ion cells. When overheated, these cells can start to leak corrosive electrolytes, resulting in swelling or rupture of the battery. This can damage the phone’s internals.
Component failure
The microchips and circuit boards inside phones are designed to operate at certain temperatures, usually below 95°F. In extreme car heat, delicate components can malfunction or fail permanently.
Display damage
The adhesives securing phone display panels can soften at high temps. This allows air pockets to form underneath the display, appearing as distorting bubbles under the glass. Displays can also sustain permanent burn-in damage.
Tips to keep your phone cool
Here are some simple but effective ways to avoid phone overheating when leaving it in a hot car:
Create shade
One of the easiest ways to reduce interior heat is to shade the inside of the car from direct sunlight. Use sun shades on the windshield and windows.Park in the shade beneath trees or cover the windows with reflective sun shields. This prevents the greenhouse effect from developing.
Insulate with tint
Getting quality tint installed on your car windows can drastically reduce heat buildup. Metallic tint films are best, as they reflect more solar radiation away from the car. Ceramic tint also provides excellent heat insulation for a parked car.
Crack windows & doors
Leaving your windows cracked open a few inches allows hot interior air to escape the car, being replaced by fresh breezes. This ventilation can prevent temperatures from rising excessively. But take care not to leave windows open enough to allow rain in or enable theft.
Use a sun shade
Windshield sun shades are inexpensive and highly effective at cooling interiors. Foil or canvas shades reflect sunlight back out the windshield before it can heat up the dashboard and seats. A sun shade prevents the greenhouse effect from developing.
Choose light colors
Lighter vehicle colors reflect more sunlight, absorbing less heat. White, silver, tan, and light blue paint jobs all stay cooler in summer sun compared to dark colors like black and navy. So parking a lighter colored car in the sun would result in a cooler interior than a darker vehicle.
Vent with a fan
Battery powered fans can enhance airflow through cracked windows, rapidly venting hot interior air. Just be sure to position the fan properly so it blows air out of the car, not just circulates it inside. Fans that mount in cup holders work well for venting.
Park in a garage
The best way to minimize solar heating is to park your car in a shaded garage. Home or commercial parking garages prevent sunlight from reaching your vehicle at all. The interior will remain very cool even on hot sunny days. Outdoor carports also provide useful shade.
Use reflective shades
There are custom fit sun shades made with highly reflective metallic coatings. These effectively block and reflect away almost all solar radiation, reducing interior heat substantially. Some even have grommets so you can keep your windows cracked while the shade remains in place.
Choose glass tinting
Factory privacy glass found on some vehicles provides a basic level of heat protection. But getting high performance ceramic window tinting professionally installed can keep interior temps much cooler. Quality tinting blocks 50-70% of incoming solar energy.
Cover with a blanket
An improvised way to shade the interior is by covering the windshield and windows with towels or blankets. Use silver-coated “space” blankets or light colored towels to reflect more sunlight away. Just be sure your makeshift covers won’t scratch the glass or blow away.
Keep it low
Heat rises, so the coolest spot in a hot car is down near the floorboards. Keep phones and other temperature sensitive items on the floor, under seats, or in the center console rather than on the dashboard or seats. The rear footwell area stays remarkably cool.
Stash in the trunk
Car trunks are separated from the main cabin, essentially acting like coolers. The interior of the trunk often remains significantly cooler. Just don’t leave your phone in a hot parked trunk for more than short periods, as it can still overheat.
Insulate with towels
Wrapping your phone in towels acts as insulation to block heat absorption. Use light colored towels or even small styrofoam cooler packs wrapped in towels to provide a buffer against the hot interior. Just don’t seal phones in air-tight due to moisture concerns.
Leave it home
Of course, the simplest way to ensure your phone stays cool is to not leave it in a hot parked car in the first place.Bring it with you when exiting or lock it in a cooled interior space like your home or office. This eliminates any overheating risk.
Using phone cooling accessories
There are various phone accessories designed to either cool your device or protect it from heat:
Cooling cases
Phone cases made from metals like aluminum alloy conduct heat away from your phone. Some feature fans to generate cooling airflow. Others utilize chilled gel packs. These cases help moderate device temps.
Sun shields
Mini pop-up phone shades are available that either attach to your device or sit between the phone and window to block solar radiation. Like car window screens, these reflect sunlight and cut heat absorption.
Vent mounts
Air vent phone mounts position your device directly in the cooling airstream from a car’s AC system. The constant flow of chilled air keeps your phone from overheating by ventilating it.
USB fans
Small battery powered fans can be plugged into smartphones via USB port. They generate a cooling breeze that isolates the phone from hot interior air and lowers operating temperature.
Reflective skins
Heat reflective metallic foil skins cover the back and sides of phones to reflect solar energy. By bouncing sunlight away they reduce thermal buildup inside the device.
Identifying heat damage
How can you tell if your phone has sustained heat related damage from a hot car? Here are signs to look for:
Swollen battery
Excessive internal air pressure in lithium ion batteries causes swelling. This warps the phone’s housing, causing the case to bulge outward. This is a surefire indicator of overheating damage.
Random restarts
If your phone starts spontaneously restarting or powering down without reason, overheated chips may be malfunctioning. The processor or RAM cannot operate properly at abnormally high temperatures.
Discoloration
Extreme heat can cause the adhesives and polymers in a phone to break down. This leads to visible discoloration of the display frame, buttons, or back housing. You may see brownish or yellowish staining.
Cracked glass
Rapid temperature changes, like hot air to cold air, can fracture glass phone screens. Cracks tend to form near edges and chip outward if phone glass has sustained thermal stress damage.
Distorted display
Excess heat rises in the display, creating visible air pockets and bubbles between the glass and LCD below. This refracts the screen image into distorted blotches and ripples.
Dead pixels
Individual pixels in OLED displays can die from overheating, appearing as tiny permanent black dots on the screen. Heat damage causes these individual LEDs to fail.
Reduced performance
If phone processors reach excessively high temperatures, they may throttle down processing speed to cut heat output. So slow operation, freezing, and glitching apps can mean a phone was heat damaged.
Failed touchscreen
The digitizer film beneath your phone’s display can detach or sustain damage when overheated. This leads to an unresponsive touchscreen. Parts of the screen may not register taps and gestures.
Speaker popping
Tinny or distorted audio from speakers can indicate heat damage. The voice coils in speakers can warp and deform when subjected to high heat levels inside a car.
Repairing heat damage
Here are your options if your smartphone did sustain heat related damage:
Replace battery
If the battery is bulging but the rest of the phone functions normally, a battery swap may be all that’s needed. Phone repair shops can source quality replacement batteries and perform safe installations.
Component-level repair
For issues like failed processors, soldered ports, or damaged charge circuits, component-level microsoldering can potentially restore full functionality. Professional phone repair techs have the skills for this.
Full device replacement
If there is extensive motherboard failure or the display glass is badly cracked, it may not be cost-effective to repair an older phone. Buying a quality used/refurbished phone or new device from the same model line is easiest.
Use phone cooling accessories
Going forward, using phone cooling cases, shields, mounts, and other accessories can help prevent heat damage from recurring. Proactive temperature management is wise.
Avoid leaving phones in hot cars
Altering habits to never leave devices in sun-exposed vehicles for prolonged periods is the simplest solution. Take phones with you or store them in climate controlled spaces to avoid overheating. Prevention is ideal.
Conclusion
Leaving phones in hot parked cars, even briefly, can expose them to temperatures high enough to cause serious damage. Battery swelling, component failure, display damage, and loss of functionality can all result. Safeguard your smartphone by parking in shade, ventilating your car, using reflective shields, and keeping phones low and insulated. Proper precautions and cooling accessories can help avoid the risks. But it’s always best to take your device with you rather than leaving it unprotected in sweltering car interiors. With extra care, you can prevent excessive heat from damaging your invaluable phone.