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How To Keep an Amp in the Trunk Cool (9 Tips and Tricks)

One of the best ways to enhance in-car entertainment is with a good sound system. There’s nothing like putting on your favorite tunes to help you deal with the rush hour traffic. Upgrading your speakers and installing a powerful amplifier can elevate the experience, but since you can spend hours behind the wheel, how do you keep your amplifier from overheating?

Here are 9 tips and tricks to keeping your amplifier in the trunk cool:

  1. Choose an amplifier that is less prone to heating.
  2. Ensure the amplifier and speakers are compatible.
  3. Make sure the ground connection is good and secure.
  4. Use a grounding wire with the correct size and power.
  5. Place the amplifier in an area with good ventilation.
  6. Allow the heat in your trunk to dissipate.
  7. Install an amplifier cooling fan.
  8. Install a heat sink.
  9. Don’t overwork your amplifier.

In this article, I will discuss the different ways you can keep the amp in your trunk cool. These tips will enable you to continue listening to music without worrying about overheating. So, keep reading to learn all you can on this topic and discover some useful tricks that can come in handy.

Car amp

1. Choose an Amplifier That Is Less Prone to Heating

You can install various amplifiers for your car’s audio setup, but the type of amp you use significantly determines its tendency to overheat. If you want to keep the amplifier in your trunk cool, you should start by choosing one that doesn’t generate a lot of heat.

Amplifiers usually fall under one of the following categories:

  • Class A
  • Class B
  • Class AB
  • Class D

Each class determines the amplifier’s power, sound quality, and efficiency.

Class A Amplifiers

Class A amplifiers are hardly used in automotive audio despite having superior sound quality since they are the least efficient.

An amplifier’s efficiency is defined by how much electricity it needs to generate the power it’s capable of sending to the speakers. Hypothetically, if a 150-watt amp had an efficiency of 100%, it would only need 150 watts of electricity to reach its peak power output.

The efficiency of a class A amplifier is usually in the neighborhood of 30%. This means it would need 500 watts of input power to generate an output of 150 watts, making it run a lot hotter.

To put it simply, an amplifier with an efficiency rating of 30% will only turn 30% of the power it receives into sound, while the remaining 70% is turned into heat.

Another trait of Class A amplifiers is that they are always on. The internal circuitry of Class A amps keeps a current passing through their output transistors, which also contributes to more heat.

Aside from generating a lot of heat, Class A amplifiers also take up a lot of space, making them impractical for car audio applications.

Class B Amplifiers

Unlike Class A amplifiers, Class B amps are switched, so the output transistors are off when there is no audio signal to process. This design makes Class B amplifiers more efficient and less prone to heating up.

The downside of using Class B amplifiers is that they don’t offer as much fidelity since they produce more distortion.

So, if you hold sound quality in high regard, you’re much better off with another amp in your car, even if Class B amplifiers run cooler.

Class AB Amplifiers

As the name suggests, Class AB amplifiers give you the best of both worlds. Like Class A amplifiers, they are always on, but their internal circuitry uses less power when no audio signal is present.

Class AB amplifiers are efficient, so they’ll not produce as much heat as a Class A amplifier. 

The best part is that they generate less heat without compromising power and good sound quality, making them suitable for car audio setups.

Class D Amplifiers

Class D amplifiers are the most efficient. They generate very little heat, making them popular for car audio applications.

Like Class B amplifiers, Class D is also switched, but the difference is that these amps can switch the current to their transistors on and off much quicker.

The main disadvantage of using a Class D amplifier is that their pulsed sound signal suffers from distortion at higher frequencies.

Also, Class D amplifiers are quite powerful, but since there’s a noticeable dip in sound quality at higher frequencies, they are better suited for powering subwoofers.

You can still use a Class D amplifier to power full-range speakers and correct the sound through equalization or a low-pass filter.

In fact, as already mentioned, Class D amplifiers are one of the most popular choices when it comes to car audio since they hardly generate any heat.

Car speakers and amp

2. Ensure the Amplifier and Speakers Are Compatible

Even if you use an efficient amplifier that generates less heat, to keep the amp cool, you also have to ensure that it is compatible with your car’s speakers.

So, before buying an amplifier, check your speakers’ impedance and RMS (root mean square) values.


Impedance is measured in ohms and is the amount of resistance the current of an amplifier has to overcome to power a speaker. Speakers with lower impedance (or resistance) allow more current to flow.

It’s essential to consider your speakers’ impedance when selecting an amplifier.

If the impedance is lower than what the amplifier can supply, it will cause the amp to cut out and overheat. Most amplifiers can work with speakers with an impedance of 4 to 16 ohms.


Both speakers and amplifiers have an RMS power rating measured in watts.

Without getting too technical, RMS is basically the amount of power your speakers are capable of handling and the amount of power your amp can put out.

Always make sure that the power output of your amplifier is equal to or greater than the RMS rating of your speakers.

Underpowering your speakers will cause your amplifier to overheat.

Let’s say your car has four speakers, each with an RMS power rating of 50 watts and you use an amplifier rated at 25 watts per channel. As you turn up the volume, it will reach the point where the amplifier will struggle to supply power and cause it to overheat.

Many experts recommend getting an amp with a power output that is the same or 1.5 times more than the speakers can handle.

3. Make Sure the Ground Connection Is Good and Secure

Once you’ve chosen a suitable amplifier, the next step to ensuring the amp stays cool is making sure it’s installed correctly. A critical step in the installation is making sure there’s a good ground connection.

Without a proper ground connection, your amplifier can overheat or cause short circuits and the car’s fuses to blow. Hence the black wire from your amplifier must have a secure connection to the bare metal of your car’s chassis.

4. Use a Grounding Wire With the Correct Size and Power

Aside from ensuring your amplifier has a good ground connection, you also have to make sure the wires are big enough to handle all the power. A wire’s thickness or gauge determines its resistance and load-carrying capacity.

The size of your wires will depend on the type of amplifier you use and how much power they put out. Note that using extremely thin wires can cause your amplifier to overheat or even shut down. provides formulas and a chart to help you determine the best wires to use for your car’s audio system.

You can also purchase grounding kits that give you all the wires you need for your car’s audio upgrade.

The Elite Audio Grounding Kit (available at comes with 4 gauge wires, capable of handling some serious power.

5. Place the Amplifier in an Area With Good Ventilation

Another vital factor to consider during installation is where to put the amplifier. Make sure to place it in an area with good ventilation.

You also want to avoid placing the amplifier in areas with tight crevices in your trunk. There needs to be good airflow around the amplifier to keep it from getting hot.

Some amplifiers have grilles, and you have to make sure they remain unobstructed.

Even if amplifiers have a solid base, it’s always good to use adaptor plates or place a piece of wood between the mounting points to give the amp some room to breathe.

6. Allow the Heat in Your Trunk To Dissipate

You can also control the temperature in your trunk to a certain extent by allowing the heat to dissipate after exposure to high temperatures.

Amplifiers remain cool when not in use, but if the ambient temperature rises, the amp will heat up faster once it’s turned on. Hence, it’s best to park in shaded areas as much as possible. However, if you can’t avoid parking under the sun, open the trunk to let cool air in before driving off.

If your car has split-folding rear seats, it also helps to fold them if there isn’t anyone sitting at the back. This allows the air-conditioning to circulate in the trunk.

7. Install an Amplifier Cooling Fan

Since a car’s cargo area is often enclosed, it also helps to install a cooling fan to keep your amplifier from overheating. The fan supplies the amplifier with the air needed to keep it cool.

Most cooling fans are easy to install and run on 12 volts. Install the fan next to the amplifier, making sure the air flows towards the amp as much as possible.

The Xscorpion TF8 Cooling Fan (available on is compatible with all 12-volt systems and has mounting tabs for easy installation.

8. Install a Heat Sink

A more complicated but effective way to deal with heat in your amplifiers is to install a heatsink on the board of your amplifier.

A heat sink’s objective is to dissipate heat by increasing the surface area that comes into contact with air.

Many car amplifiers have internal and external heat sinks that look like fins and ridges. 

If you’re up to the task and there’s enough room on your amplifier board to accommodate it, you can install an additional heat sink. Heat sinks are affordable and come in different sizes to fit various applications.

Here’s a video demonstrating how to add heat sink to a class D amplifier board:

9. Don’t Overwork Your Amplifier

This last tip is the most basic one, and it simply involves keeping the volume, gain, and bass at conservative levels.

It may seem counterintuitive because the whole point of installing an amplifier is to make your sound system louder, but it doesn’t mean that you can never crank the volume up.

Amplifiers consume more power as you increase the volume, making them more prone to overheating.

There’s no harm in playing loud music for a song or two, but demanding a lot of power from your amp for extended periods can strain it and cause it to overheat. 

Some car amplifiers shut down or go into protect mode when overworked to prevent any severe damage from occurring. Allowing your amplifier to rest should get it out of protect mode. However, if that doesn’t do the trick, you may have to disconnect and reconnect all the wires to the amp for it to work again.

Key Takeaways

Upgrading your car’s audio system can turn your daily commute from boring to fun and exciting. An amplifier helps you obtain the best sound from your speaker but an amp that constantly overheats can ruin your experience.

Keep your amplifier cool by:

  • Choosing a Class AB or Class D amplifier that’s compatible with your speakers.
  • Placing the amplifier in a well-ventilated area.
  • Installing a cooling fan to keep your trunk cool.
  • Parking in the shade.
  • Avoiding playing music at high volume for extended periods.

Follow these tips to enjoy listening to music in your car while keeping your amplifier cool.