PC ComponentsPower Supply

How Long Should a Power Supply Last?


The power supply unit (PSU) is an integral part of a computer setup. The PSU’s main function is to convert AC into DC and regulate the amount of DC output so it’s usable by your computer component. When shopping for a power supply unit for your computer, there are many questions to ask yourself. But one important question is how long a power supply should last.

Quick Answer

Generally, the power supply unit of your computer should last an average of 4 to 5 years. But if you are using the computer extensively 24/7, then the longevity of the PSU will decline faster. The primary cause PSU gives out is due to mechanical stresses, power surges, heat, aged capacity, and other components. 

If you purchase a reputable brand, PSUs are a component of your computer that you can carry over to a new build. So, unless you upgrade certain components on your computer and need more power, you don’t need to consider replacing the PSU of your computer. But ensure you keep an eye out for signs of degradation of the PSU so you can replace them before they become hazardous.

Continue reading this article to learn more about the longevity of a power supply unit. 

What Influences the Lifespan of a Power Supply Unit? 

The power supply unit on your computer comprises circuit boards and components soldered and assembled onto it. The degradation of these various components plays a crucial role in the longevity of the PSU on your computer. 

Below are some of the components of a PSU that can influence its lifespan.  

Factor #1: Capacitors 

Capacitors are perhaps the most common component in the PSU that causes electronic faults. When this component is in your PSU age, the capacitance value is altered, changing the power supply’s efficiency compared to its original design. 

While the lifespan of this type of capacitor is hard to predict, if the electrolyte starts to evaporate, the capacitor will no longer function as well. Most PSUs use an aluminum electrolytic capacitor which is quite different from regular capacitors. An aluminum electrolytic capacitor is made with aluminum oxide as a dielectric and pure aluminum foil

Factor #2: Resistors 

Another important component in the PSU of computers is the resistors, commonly referred to as carbon resistors. Similarly, when they start to age, it alters their resistive value

By nature, the heat exchange from electrical to thermal causes resistors to slowly increase in value. This increase doesn’t particularly hurt the capacitor, but it can cause some irregularities, which can cause other components in your computer not to get enough supply.

Generally, when the power rating of a resistor is too low for a task, the degrading effect of the resistor accelerates. Sometimes this scenario plays out when an appropriate value isn’t chosen for the circuit’s design.  

Factor #3: Transformers, Inductors, and Coils

The transformer, inductor, and coils are the most reliable component in the PSU of your computer. While they are not the most likely component to cause a power supply to fail, they can still become faulty with time. But most of the time, these components of a PSU tend to fail due to power design

The transformer, inductor, and coils are copper wires coated with enamel wrapped around a magnetic core, ferrite, or plastic. Some inductors in a PSU are wound with thicker wires, which is the ideal design for building a powerful computer that would demand much power. 

Factor #4: Integrated Circuits 

You would also find integrated circuits in the PSU of computers. The lifespan of these components depends on a couple of factors. For example, how hot the component gets over time can influence how long you expect the integrated circuit to last. Also, the type of electricity supplied to the unit will determine how long the unit lasts.

Overall, the integrated circuit in a PSU is heat and electricity-sensitive, so when there is a deviation, it shortens the lifespan. Poor manufacturing standards can cause the integrated circuit to last a short period. So, when shopping for a PSU, you want to aim for one from a reputable manufacturer.  

Factor #5: Other Semiconductors 

Other semiconductors in a PSU, like diodes, transistors, voltage regulators, etc., also play a crucial role in the lifespan. The voltage going into the component of a PSU must be stabilized and kept as intended. But when the intake voltage exceeds the specified value, it can damage these semiconductors and other components in the PSU. Also, with time and through many heating and cooling cycles, these semiconductors will lose efficiency and produce current leakages.  

Factor #6: Cooling Fans 

A PSU also comes with a cooling fan which helps to keep the unit at an optimal temperature. But like other components in the PSU, it can get old, causing the bearing inside to cease up and the fan not to spin at all or spin slowly.

Suppose there is an issue with the cooling fan of a PSU. In that case, while the PSU might still supply power, it’s not recommended to keep using it in this condition, as high temperature can damage another sensitive component in the PSU. 

Keep in Mind

Unlike desktop computers, laptops do not have a fully dedicated power supply. However, a laptop must be supplied with DC to charge its internal battery.


Overall, many variables determine how long a PSU lasts. However, the components can be unpredictable, and the specific age it will last can be very difficult to pinpoint. But proper maintenance and attention to when a certain component is failing and replacing it on time can help you get more years out of the PSU. 

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