4 Types of Spark Plugs – Why Iridium is too much expensive?

What is the role of a spark plug?

A spark plug is an essential part of the engine’s combustion process used in spark-ignited engines (generally gasoline). It plays an important role in the combustion process and provides the engine with the needed spark in the compression stage.

Source: Testing Autos

Wear and residues on the tip of the plug that is known as the center electrode could lead to many problems, such as engine misfiring and poor fuel economy.

Source: championautoparts

For this reason, it is crucial to choose a suitable spark plug for your car, and here comes the most expensive spark plug, the iridium spark plug.

Why is the iridium spark plug that much expensive? And is it worth it to use it in our engines?

Factors affecting spark plug selection

Source: autoguru

When selecting a spark plug for your engine, there are multiple points that you need to take into your consideration.


Depending on the type you are choosing, the price varies widely. You might consider some types to be costly and not worth extra money, which might be true in some cases.

The price will depend mostly on the type of material used in the production of the electrodes. Usually spark plug prices range from $10 to $100.


Some types would last little, and some would last way more. You might be a person that doesn’t mind changing the spark plug more frequently, so this point will not bother you.

But it is a point to consider while comparing, and don’t forget the cost of changing the spark plug and the troubles you might get in if your spark plug starts malfunctioning. Usually spark plugs would last from 20,000 mile to 100,000+ mile.

Special Requirements

In some cases, you must compile with your car’s manufacturer guidelines and stick to one type. There are also some cases that you require a specific type depending on the system your car works in.

Spark plug types

When we are talking about “types” here, we mean the type of material used in the center electrode. Usually, most of the spark plug’s center electrodes are made of copper in their core but are coated with another outer layer material.

Source: wonkeedonkeetools

Let’s take a look at the different types available in the market:

Copper Spark Plug

Source: Cash Car Buyers

This is known as the common spark plug. It is widely used among different vehicles, and it is one of the oldest spark plugs in the market. It has a copper core but is coated with nickel alloy.

  • Pros: 
    • Inexpensive due to material used. 
    • Colder than other spark plugs for this reason it is often used with turbocharged engines.
  • Cons:
    • Relatively low melting point, which means that the electrode could wear quickly.
    • Bigger center electrode diameter, which means it needs more voltage to generate a spark.
  • Lifespan:
    • Up to 20,000 miles.
  • Price:
    • Starting from $2 per plug

Silver Spark Plug

Source: Bosch Auto Parts

Silver spark plugs are not commonly used that much nowadays. It was used mainly in old European performance cars and motorcycles.

  • Pros:
    • It provides a really high thermal conductivity.
    • It requires low voltage to produce spark.
  • Cons:
    • More expensive than copper.
  • Lifespan:
    • Between 20,000 to 30,000 mile
  • Price:
    • Starting from $5 per plug

Single Platinum Spark Plug

Source: acdelco

This type of plug provides more life span than copper or silver. It is made of platinum, the strong material.

  • Pros:
    • Center electrode have platinum disc which is a strong metal that will last longer.
    • It generates more heat, which means it will reduce carbon build-up on the plug.
  • Cons:
    • More expensive than copper and silver.
  • Lifespan:
    • Up to 100,000 miles
  • Price:
    • Starting from $10 per plug
Source: advanceautoparts

This spark plug is usually recommended for coil-on-plug ignition system cars.

Double Platinum Spark Plug

This plug uses the same material explained above. It’s the platinum. But this time, it is doubled!

Platinum is coated (or discs) on both the center and ground electrodes, and thus it has a longer lifespan compared to single platinum plugs. This type is recommended for wasted spark ignition systems, which exert more wear on both the center and ground electrodes.

  • Pros:
    • Made of platinum which is strong material.
    • It generates more heat, which means it will reduce carbon build-up on the plug.
  • Cons:
    • More expensive than copper, silver, and single platinum.
  • Lifespan:
    • More than 100,000 miles
  • Price:
    • Starting from $20 per plug
Source: advanceautoparts

In this system, the plug sparks twice in each complete cycle, once in the compression stage (as in other systems) and the second during the exhaust stage (which is a wasted spark).

The double plug will last longer than the single, but it will have a higher price, no doubt.

Iridium Spark Plug

Source: Ma Performance

This precious material provides a great advantage for the spark plug industry. 

It could easily last for more than 100,000 miles before it needs to be changed. 

  • Pros:
    • It has the smallest center electrode tip diameter that requires a lower voltage to produce the spark.
    • It is 6 times harder than platinum and has a 700°C higher melting point.
  • Cons:
    • This spark plug is the most expensive among all.
  • Lifespan:
    • Between 100,000 to 200,000 miles
  • Price:
    • Starting from $20 per plug and up to $100

Many car manufacturers are now producing their vehicles with iridium spark plugs that are actually providing greater performance and a better driving experience.

Why Iridium Spark Plug is expensive and is it worth it?

This precious material costs more than $5,000 per ounce, which means that it is the most expensive material used in spark plugs production. It is way more expensive than gold that worth $1,800 per ounce.

Source: Rare World Metals Mint

Depending on the manufacturer and other features, this spark plug price could be more than $20 per plug!

Yes, it is costly for this small part in the engine to pay up to $100 for the set, but you are getting a lot for this price.

So is it worth it?

From my point of view, the first thing you have to ask is, can I use it? You have to stick with your car manufacturer’s recommendations before choosing which to buy. Ask a technician and find if you could upgrade or not.

If you are really willing to change the spark plugs less frequently and would love to have fewer problems and stops with your car, then the upgrade is really worth it.

Source: Desert Oasis European Auto Service

Who doesn’t love things that last longer? Having to change your spark plugs every 10,000 to 20,000 miles could be frustrating.

When taking into consideration the time and money, you will pay for changing the plugs, then using an “expensive” spark plugs could be cheaper!

We would like to hear from you any information or experience you have with iridium spark plugs.

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