What Is A Pre-Filter In An Air Purifier? – How Does The Pre-Filter Work?

The mechanism of the air purifier is mostly simple. In most cases, there will be an intake fan and a filtration unit.

The fan will make the air go through the filter, which will capture the pollutants and let out clean air.

But, some devices have a pre-filter. So, what is a pre-filter in an air purifier?

The pre-filter in an air purifier is basically a prescreening filtration unit. Its primary task is to take care of large particles in the air. As a result, it makes things easier for the primary filter.

But what elements can this filtration unit clean? Also, can you wash a pre-filter?

To know about these and more about pre-filter, you should keep reading.

Pre-Filter in Air Purifiers Explained

You can think of the pre-filters as an additional line of defense against airborne particles. But it is not really just an extra filter. It does more than that.

For example, pre-filters remove the large particles that can clog up a primary filter.

And in the worst-case scenario, the central filtration unit can get severely damaged.

In other words, most air purifiers have a pre-filter to extend the life of the primary filter.

The thing is, air purifiers are not just for residential use. Commercial places also rely on these devices to keep indoor air quality high.

The particles present in commercial places are not the same as the ones in residential environments. Basically, the air of commercial space has more airborne particles.

That is why air purifiers with pre-filters make the most sense in such environments.

How Does a Pre-filter Work?

To understand how the pre-filter works, you must first know where it is placed in the air purifier.

So, the central filtration unit will be behind the intake fan in regular devices. But the case is different for the devices with pre-filters.

This additional filtration unit will be between the primary filter and the intake air.

That means the intake air will first make the air go through the pre-filter. And when the air passes through it, the pre-filter will clear out most of the large-sized particles.

But what particles can pre-filters clean?

Most of the large particles will get trapped in the pre-filter. That includes pollen, insects, hair, dust, and different types of fibers.

Even though the pre-filters cannot take all the pollutants out of the air, they play a crucial role.

All the particles that pre-filters take out can make the primary filter wear out faster.

That means you will not need to replace the primary filter that often if your air purifier comes with a pre-filter.

What Is the Difference Between HEPA Filter and Pre-filter?

HEPA filters and pre-filters are totally different things. Let’s give you an overview of the factors that make them different –

HEPA Filter Is a Primary Filter

The HEPA filter you find in air purifiers is the primary filtration unit of the device.

That means it is there to take most of the load if not all of them. It takes care of both large and small pollutants.

Pre-Filters Are Washable

Another key difference between HEPA filters and pre-filters is that the pre-filters are washable. You can take the pre-filter out and wash them under water.

And the main thing is that you can wash them periodically. The same thing is not true for most of the HEPA filters.

Pre-Filters Are Extra Filters of the Air Purifier

As stated earlier, HEPA filters are the primary filter of air purifiers. A device meant to work with a HEPA filter will not work without it.

On the other hand, if you take the pre-filter out of the air purification device, it will still work as long as the primary filter is okay.

How Do You Clean a Pre-filter Air Purifier?

The additional filter found in the air purifiers is pretty easy to clean. You just need to go through the following steps –

Turn the Air Purifier off and Unplug It

Before anything else, you must ensure that the air purifier is off. Also, for additional safety, take the plug out of the outlet.

Do not pull by holding the wire. You might accidentally damage the plug.

Instead, hold the plug’s holding part (meaty area behind the socket) and unplug it.

Take the Pre-Filter Out

After turning the air purification device off, you need to remove the pre-filter.

Generally, you will not need to handle any tools to get it out. Just pulling on the cover should do the trick.

However, when you are trying to get the pre-filter out, make sure that you are keeping a plastic bag underneath it.

Because a lot of particles could be lodged into the pre-filter, which can directly fall onto the floor when you remove it.

Also, pay proper attention to the orientation of the pre-filter before taking it out. This information will come in handy when you have to place the unit back in place.

Dust and Wash the Pre-Filter

Take the pre-filter outside and dust it off. You can even use a vacuum cleaner if you want to. Afterward, hold the pre-filter under running water.

Make sure that the water is cold or mildly warm.

Beware of using hot water, as hot water can damage the fiber of the filter, which will require you to replace it sooner than later.

Let the Pre-Filter Dry Up

Do not place the pre-filter back into the air purifier while it is wet. Instead, you need to leave it to dry.

Just keep the unit in an open area with sunlight for 24 hours, and it should dry up.

No matter what, do not try to speed up the process by using a hair dryer or clothes dryer. That will, again, damage the unit.

Put the Pre-Filter Back in Place

Once the pre-filter dries up, it will be time to put the unit back into the slot.

Make sure that the filter latches properly and the orientation is correct. Otherwise, it will not work as it should.

Can You Use Pre-Filters on Any Air Purifier?

You can put a pre-filter on any air purifier. Yes, even if your air purifier does not come with this additional filter, you can still enjoy all the things that pre-filters bring to the table.

We have tailored a step-by-step process for your ease. You just need to go through these simple steps –

  1. Turn the air purifier off.
  2. Unplug the air purifier from the wall.
  3. Locate the intake vents of the air purifier and take note of their dimensions.
  4. Cut the pre-filter according to the dimensions of the intake vents.
  5. Attach the pre-filter to your air purifier.

When attaching the pre-filter to your air purifier, you should be extra careful. No matter what, you do not want to block the intake vents of the air purifier.

If you block them, the device will not be able to take the air inside properly. And that would result in the air purifier being less effective.

Also, in terms of attaching the pre-filter, you can use tape or non-permanent adhesive. Again, be extra careful when using these.

Frequently Asked Questions

1. Do I need a pre-filter on my air purifier?

It is a good idea to get a pre-filter on your air purifier. This additional filter will make it easier for the main filter to clear out the pollutants from the air. Also, you will not need to change the primary filter that often as the particles that clog up filters will not reach it.

2. How often should you change the pre-filter in an air purifier?

The pre-filter needs to be washed periodically. And you should only replace it when it is damaged or has signs of wear. Generally, they should last anywhere from 6 months to 12 months.

3. What is a pre-filter in a HEPA filter?

The pre-filter in the HEPA filter collects hair and dust from the air. As the large particles do not reach the HEPA filter, the unit will last longer. So, the pre-filter will basically save you from changing the filter frequently.

Read More: What Is A True HEPA Filter?

Final Words

Are you still wondering what is a pre-filter in an air purifier? Think of like as an additional filter for the air purification device.

This extra filter will clear out the large particles from the air before it reaches the primary filter. As a result, the main filter lasts longer and does not clog easily.

Last Updated on January 14, 2023

Richard Hicks

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