Do Car Trunks Get Hot? Basic Facts (With Numbers)

While we may think the trunk of cars isn’t as important as the vehicle, it is very essential for storage in cars. It is where your luggage, groceries, and other items stay when driving.

However, there are items, especially edibles that we can’t store in high temperatures. While the interior of cars is liable to get hot, you may wonder if it includes the trunk.

In this article, we will discuss if the trunks of cars get hot and all about car trunk ventilation. To know more, read along as we dive into this topic.

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Here’s the answer to whether the trunks of cars get hot:

The trunks of cars will get hot depending on factors like the temperature of the sun, where drivers parked them, the volume of the trunk, ventilation, color of paint, and the materials manufacturers used to build them, among others. 

The trunk of cars doesn’t always get as hot as the passenger compartment of most cars. This is because it doesn’t have windows, thus heat won’t penetrate it as it does the passenger compartment.

Also, how manufacturers insulate your car has a vital role in determining if its trunk gets hot. Car trunks that manufacturers insulated very well block heat, while car trunks that car manufacturers do not insulate very well will get hot when owners expose them to heat.

How Hot Does the Trunk of a Car Get In Direct Sunlight?

How hot the trunks of cars get depends on the temperature of the sun and how long owners expose the cars to the sun.

The car trunk will get hot when it traps the sun’s infrared wave in its interior. The infrared wave your car traps in the trunk becomes heat, making your car hot.

The inability of the trapped infrared wave radiation to escape from the car trunk over a long period will lead to a hot trunk.

However, how hot the trunk of a car gets will depend on how hot the sun is, and how much heat the car’s rear windscreen has trapped in the trunk through the passenger compartment.

It also depends on whether there is any cooling agent in the car trunk.

The trunk of cars can get as hot as 130 to 150 degrees when owners park cars in direct sunlight with a temperature range of 80 to 95 degrees within an hour without an active cooling agent. It can be higher if the temperature is higher and vice versa.

However, the availability of reflectors can help control the heat in your trunk by reflecting the sunlight. Car owners can keep reflectors along the windscreen of cars.

Also, keeping windows slightly down will help reduce how hot the trunk of cars can get. This will maintain ventilation and make room for hot air to circulate out of the car.

Meanwhile, explore some affordable cars with long hoods.

Is the Trunk of Car the Coolest Part of the Car?

The trunk may or may not be the coolest part of the car, depending on some factors. These factors include the climate and car features, such as the color and the installation of an insulator.

The temperature of the trunk of a car stays around the ambient temperature of the environment. In a cold climate, the trunks of most cars are the coolest. Cold climates include when the day isn’t too hot, or during the colder seasons of fall and winter.

There is a higher chance that the trunk is the coolest part of the car during these seasons because there is nothing to keep it warm.

However, the trunk may be the hottest in a tropical climate, but there are some exceptions to this. A report stated that in some cars, e.g. sedans, the trunks are the coolest part even in hot temperatures.

Also, in some cars, the color of cars affects the temperature of the trunk. The trunk may be cooler than the other parts of the car if the color is bright, e.g. white.

In cars with darker colors, such as black, the car trunk can get warmer than the other parts. This is because the heat coming from the car exterior can make it into the car trunk’s interior.

Because of closed trunk lids, there won’t be a way for the heat to escape from the trunk. And will make the trunk hotter than the other parts of the car.

However, cars with insulators will have the trunk as the coolest part of the car. Insulators prevent heat from the car’s exterior from warming the trunk of a car. Especially on hot days. The adoption of the insulator is one of the best ways to keep the trunk of a car cool.

When buying an insulator, note that manufacturers design some insulators to fit specific car models’ trunks, while others can fit most car models.

Related: 14 Popular Cars With Extra Big Trunks (With Pictures)

Does the Trunk Get As Hot As Inside the Car?

The trunk doesn’t get as hot as inside the car in most cars. This is because the cabin has windows that generate heat, unlike the trunk.

The heat inside the car cabin can be dangerously high and can reach up to 150 to 182 degrees when drivers park cars in direct sunlight. This is very high compared to the heat the trunks generate.

Also, in many cars, the trunk has a better insulator than that of the cabin, thus making it cooler. The insulator will prevent hot air from circulating in the trunk, but not in the cabin. For cabins with insulators, these insulators have lower heat control compared to the ones in the trunk.

To verify the trunk doesn’t get as hot as the inside of the car, most temperature experiments have produced results that verify the interior is always hotter than the trunk.

One of these experiments is the one My Auto DIY carried out on a sunny day with an ambient temperature of 35.5 degrees Celsius. The car sat in direct sunlight for 40 minutes while the experimenter placed two thermometers in the car, one in the cabin and the other in the trunk, at the same time.

The thermometer in the car cabin read 43 degrees, while the one in the trunk read 38.5 degrees. This verifies the trunk doesn’t get as hot as inside the car in most cases. And also that the trunk may be safer than the cabin to keeping certain items that are heat sensitive.

Related: 8 Great Cars With Trunk In The Front (With Pictures)

Is There Any Ventilation in the Trunk of a Car?

There is ventilation in the trunk of a car. In cars, the vent in the trunk lets in air from the passenger compartment into the trunk. Also, the air that comes into the trunk from the passenger compartment escapes through these vents in the trunks.

If this is not the case, the interior will pressurize to some extent and cause the effectiveness of the ventilation to decrease, leading to a lack of fresh air in the car. Also, the outlet of air via the vents prevents the accumulation of damp, humid air in the car. This protects the car interior from rusting.

The vent in the trunk is also responsible for letting out moisture in the car by allowing the continuous circulation of fresh air from the passenger compartment into the trunk. It also helps relieve pressure in cars when passengers close the car doors and trunk lids.

Do Cars Normally Have AC in the Trunk?

Cars don’t normally have AC in the trunk. However, they have a vent that circulates airflow into the trunk via the passenger compartment. The vent is also responsible for circulating air that comes out of the AC in the cabin into the trunk.

Also, you can buy an AC for the trunk of your car if you deem it necessary. There are AC products you can mount in your trunk specifically for the distribution of air in the trunk. There are options available to fit many car models. However, there are limited AC products specifically for the trunk of cars.

One of the AC products for the trunk is the Trunk Mounted Air Conditioning System, at a whopping price of $1,299. You can find this AC on some online platforms.

Related: 6 Popular Electric Cars With Spare Wheels (With Prices)

Final Thoughts

Car owners should be intentional about what they keep in the trunks of their cars. They should avoid keeping heat-sensitive products in the trunks of cars during the summer. Note that a hot trunk can reduce the effectiveness of some drugs when the heat is extreme.

Also, edibles like chocolate, fresh vegetables, etc. don’t belong in the trunks of cars as high heat can affect their taste and quality.

Cars owners should keep plastic bottled water safe by not keeping them in hot trunks. There have been reports that plastic bottle water can become harmful when consumers keep them to heat in a hot car trunk.

Also, owners should protect certain gadgets from high heat to avoid permanent damage by storing them in the trunk. Heat can affect the screen and batteries of some phones, laptops, tablets, and other tech devices.

Read here to find out why the cargo space of a car is called a “trunk”.

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