How Often Should You Replace The HEPA Filter?

When Should I Replace My HEPA Filter

As awesome as owning an air purifier is, you can’t just buy it, use it, and forget about it.

Like all appliances in the average modern-day household, air purifiers must be regularly maintained to operate at their best and serve their purpose for as long as possible.

When I bought my first HEPA filter air purifier, I had no idea it needed maintenance.

This meant any kind of cleaning or even replacing the filter itself.

Thankfully, a friend told me about it a few months into using it and that the HEPA filter needs to be replaced regularly.

I don’t even want to imagine what would have happened if I had never found out about this.

Because of my personal experience, I know that many air purifier owners also don’t know that their units must be maintained.

It needs to be cleaned, and the filter replaced to get the most out of it.

So, in today’s article, I will tell you everything you need to know about replacing your HEPA filter.

I will talk about when you need to do it, how to tell if it needs changing, how to do it, and more.

What is a HEPA Filter?

Before I tell you how often you should replace your HEPA filter, let’s start from the beginning.

That way, it will make sense when I tell you the answer.

HEPA filters are a specific type of high-quality air filtration filters that meet the HEPA filter standard.

For a HEPA filter to qualify to meet industry standards, it must be able to remove at least 99.97% of all solid particles in the air, including those as little as 0.3 microns in size.

Due to their extreme effectiveness in capturing solid particles from the air, they are the most popular type of filtration system in most modern-day air purifiers.

How Do HEPA Filters Work in Air Purifiers?

Before I get into how HEPA filters work, it’s first essential to understand how the air purifier works.

When you turn on your air purifier, the motor will start to spin the fan inside the air purifier.

This fan will then suck in air from your room, drive it through the HEPA filtration system, and release it back into your room.

Important to note that when air goes through the filtration system, 99.97% of the solid particles get stuck inside the unit, thanks to the HEPA filter.

As a result, all the air released back into the room is purified.

As for how the HEPA filter works, it doesn’t actually do anything.

It relies on the fan to drive air through it, and as I mentioned above, the solid particles get left behind during that process.

Why Does a HEPA Filter Need Changing?

Now that you know what a HEPA filter is and how it works, it’s pretty obvious why you need to change the filter regularly.

For more clarity, when the HEPA filter captures pollen, dust, hair, and other particles that are floating in the air over time, the HEPA filter will start to clog up.

This is when you need to clean your air purifier and make its life easier so it can serve you for longer.

When you regularly clean your HEPA filter, you will increase its life span, so you’ll have to replace it less often.

However, that doesn’t mean you don’t need to change it every once.

The ultra-thin fibers the HEPA filter is made of will get worn down and damaged over time.

As a result, the HEPA filter will become less effective than it once was.

Now, note that your air purifier will most likely still work as usual, except that it won’t be purifying the air as well as it once did.

If you don’t replace the filters or clean your air purifier often, it will damage the device or, worse, not turn on.

How Often Should You Change the HEPA Filter of Your Air Purifier?

I personally change the HEPA filter in my air purifier every 12 months.

That being said, I use my air purifier all the time.

It literally runs 24/7 as I enjoy breathing in clean air while I work from home and sleep during the night.

On top of that, I actively clean it, which prolongs its effectiveness.

I am fully aware that this isn’t the case for most people.

So how often you replace your HEPA filter depends on the maintenance level you conduct and how often you use your unit.

As a general rule of thumb, you should start thinking about replacing your HEPA filter after 8,000 hours.

Tracking the hours can be tricky, so the general advice if you use your air purifier daily is to change the HEPA filter every 12 to 18 months.

This is for the standard, non-washable HEPA filter.

Suppose you happen to have an air purifier with a washable HEPA filter.

In that case, you can easily use that filter for several years without worrying about replacing it.

That said, when I was in India, I bought the best air purifier for Delhi.

The air quality is some of the worst in the world, and over the 2 years I lived there, I had to change my washable HEPA filter 3 times.

How to Tell if Your HEPA Filter is Due For a Replacement?

You probably won’t be able to tell if the HEPA needs a replacement, even if you took the air purifier apart yourself.

Unless the HEPA filter is severely damaged, the naked eye can’t tell the difference between the quality of the fibers of a new and a used HEPA filter.

To tell if your HEPA filter is due for a replacement, I advise that you use a PM2.5 air quality monitor, which is also known as a particulate counter.

This device will be able to measure the quality of the air inside your home.

The best way to tell if your HEPA filter needs replacing is by measuring the air quality at different periods.

If you’re reading this and haven’t bought an air purifier, you can measure when you first get your air purifier vs. a couple of weeks later.

Or, if you already own a purifier, you can measure now and then a couple weeks from now.

That will give you a good indication of whether or not it’s time to get a new filter.

Some more complex and likely expensive air purifiers have quality control sensors.

So when your HEPA filter is due for a replacement, the air purifier will let you know.

How Do You Replace a HEPA Filter?

Unless you own a high-end model that can only be maintained by a professional, changing the HEPA filter inside your air purifier is simple.

Next, I’ll show you all the steps you should take to change the HEPA filter in your unit so you can continue reaping the benefits of your air purifier.

Get the Right Protective Gear

Before you do anything, you must ensure you have all the proper protective gear.

I recommend getting gloves (any type would work), protective goggles, and a mask.

This way, you will prevent any of the dust, hair, pollen, and mites from getting on your skin, in your eyes, or even being inhaled accidentally.

I never took these protective measures when I changed the first HEPA filter. 

And I accidentally dropped the HEPA filter on the floor.

I can’t tell you how much of the dust on the filter flew into the air and ended up in my lungs.

Take the Air Purifier Apart

I can’t exactly tell you how to take your air purifier apart since we all have different units built differently.

The best tip I can give you is to watch a YouTube video or follow the user manual that came with your air purifier when you bought it.

Most air purifiers are pretty simple in nature, so taking them apart takes a few minutes.

I currently own the Levoit Core 300, and to reach the HEPA filter, I flip it over, take off the bottom cover, and the HEPA filter is right there.

If you own a more complex unit, I would advise that you record yourself taking it apart.

That way, when the time comes to put back the air purifier, you can use the video if you get stuck.

I want to stress that your air purifier must be plugged off the wall before you start to take it apart.

Take the HEPA Filter Out and Replace It With the New One

Once you reach the HEPA filter inside your unit, pop the new one in.

The HEPA filters in most air purifiers are easy to put into place.

My HEPA filter clicks into place, and that’s how I know it’s installed correctly.

Some advanced air purifiers may have sensors that detect 

Put the Air Purifier Together

Once you’ve placed the new HEPA filter, it’s time to put everything back together.

Remember to use the user manual at all times, as that will help you take the unit apart and put it back together.

If you get stuck, refer to the recorded video of yourself taking the air purifier apart.


Depending on usage, you should ideally replace your HEPA filter every 12-18 months.

If you use your air purifier in a heavily polluted area around the clock, as I did, then replace your air purifier every 6 to 12 months.

As a general rule of thumb, you should change the HEPA filter in your unit after 8,000 hours of usage.

And remember, if you have a washable filter and take proper care of it, that can prolong its usefulness and result in you having to change it less frequently.