Air Purifier Vs HVAC Filter: Which is Better?

The quick answer?

Neither. 

They are different products that serve other purposes.

But there may be some confusion about their differences, and a lack of understanding may make homeowners wonder. 

So before dealing with the air purifier vs. HVAC filter issue, let’s clear up the differences between them first.  

Using an HVAC filter will improve the air quality in your home, but with limitations. 

Although HEPA filters can remove minute particles, they can, and do, destroy many systems thanks to reduced airflow. 

Whether a home can use a HEPA filter or not, an air purifier finishes the job an HVAC filter starts.

Bottom line? 

No matter what kind of air filter your system uses, it may not be enough to purify the air in your home. 

So can we say there’s a clear winner in the air purifier vs. HVAC filter debate? 

Read on.

Your HVAC Filter’s Job

Did you know that the first job of your HVAC filter has nothing to do with you breathing in clean air?

First and foremost, the purpose of your HVAC filter is to protect your equipment, not your health or your lungs. 

The filter plays a significant role in the efficiency and performance of your system. 

Air quality is of secondary importance. On the other hand, a standalone air purifier has one job—keeping the air you breathe clean.

It’s only in the last few decades that an increased emphasis has been placed on air quality. 

And HVAC filters began to address health issues—in addition to their role in your air handler.

Before air moves over your system’s blower, the filter removes large and or small particles—depending on what type of filter you use. 

So the air is free of particles after going through your system and back out of your supply vents.

More importantly, that debris doesn’t get the chance to interfere with the operation of your system. 

But let’s not forget that HVAC filters have a secondary job—keeping the air you breathe clean.

The efficiency and performance of a filter—how well it protects the system and your health collectively—is measured by something called MERV, which stands for Minimum Efficiency Reporting Value.

MERV ratings range from 1 to 16, with 16 being the most restrictive—it filters the smallest particles and airborne contaminants. 

So HVAC systems in hospitals are typically built to handle MERV 16. 

And thanks to COVID, many new and retrofitted commercial buildings now have systems that handle MERV 13 at least.

Of course, you also want the best air quality at home, right? 

There’s a list of things a good filter can clean from the air you breathe. 

They include:

  • Certain bacteria & germs 
  • Dust
  • Mites
  • Mold and mildew
  • Pet dander 
  • Pet hair
  • Pollen 
  • Tobacco and cooking smoke
  • VOCs (volatile organic compounds) 

Unfortunately, you can only add a MERV 16 HVAC filter if you know your system can handle it.

What do I mean by that?

HVAC systems aren’t cookie-cutter. 

Every different home has a unique system—or at least it should. 

And each system has its own airflow requirements. 

And there is a good chance a high MERV filter will restrict a significant amount of air thanks to a pressure drop in the system. 

If that goes on for any length of time, you’re looking at an expensive repair or replacement of your system’s blower motor.

If your system could use a MERV 16, “the air purifier vs. HVAC filter” battle may be clear, with the filter as the winner.

Air Purifier vs. HVAC Filter: When an HVAC Filter isn’t Enough

No two homes are precisely the same. They may be the cookie-cutter homes mentioned above. 

Still, your family, pets, furnishings, cooking habits, and more all make your home unique.

That means your air quality requirements are unique as well.

It also means that, in some cases, an HVAC filter may be sufficient. Even if your system can only take a lower MERV filter.

Here are a few possible scenarios.

If you live alone with no pets, you’re a non-smoker—at least in your home, you keep your home dust and dirt free and only eat takeout, there’s a good chance you don’t have a lot of odors or nasty things floating around in the air. 

Add to that a lack of allergies or other respiratory problems, then that filter should be enough.

On the other hand, if you have a medium to a large family, one or more furry pets, someone in the household smokes inside, and you only vacuum or dust when the bunnies start to attack, you may need an air purifier. 

Especially if you or someone in the family has respiratory troubles.

In the first of those two scenarios, those considering an air purifier vs. an HVAC filter may decide that the filter is sufficient. 

And they might be right.

When You Don’t Have a Central HVAC Filter

Depending on where you live and the age of your home, there’s a good chance your home doesn’t have a central HVAC system—and you have no HVAC filter.

You’ll know you have a central system if your home has ductwork running throughout. 

But if you heat your home with baseboard heaters or underfloor radiant heat, you’re missing out on the benefits of a good filter.

The filter collects pollutants as air passes over it.

This is different from saying portable heating, and cooling appliances don’t have filtering capabilities. 

Many—if not most—models do. 

This could include:

  • Window or portable air conditioners 
  • Mini-splits 
  • Space heaters
  • Baseboard heaters 

However, none of these will give you the kind of protection a high MERV filter could provide, and certainly not what you’d get if using an air purifier.

How Air Purifiers Work

Now that you understand how air filters work and their possible limitations, let’s talk about air purifiers. 

This will put you in a better position to choose between an air purifier vs. HVAC filter.

Air purifiers are portable, standalone appliances that have one purpose—to improve the air quality in your home. 

They do this by sanitizing the air of a variety of pollutants.

Some might wonder why they should care about indoor air quality. 

Because according to the EPA, indoor air can carry five times the amount of pollutants that outdoor air has. 

And in colder months, when your home is closed up, those pollutants are trapped inside you. 

There is no way you can escape breathing them in.

Unlike HVAC filters that remove—if they can—particles and pollutants from the air, an air purifier sanitizes the air. 

The definition of sanitizing is to make it clean and hygienic; disinfect.

For all that they do, air purifiers are relatively simplistic. They have a fan to pull in the air. 

They have a filter—or filters—typically made of paper, fiberglass, or mesh. 

Once the air moves across the filter, it is pushed back into your home. 

The amount and types of pollutants removed from your living space depending on the purifier and filter.

If you have a high-efficiency filter, they can remove particles as small as 2.5 microns, which is about the size of pet dander.

Air purifiers that use ultraviolet filters can also destroy mold and bacteria. Purifiers with activated charcoal filters can remove gases, like volatile organic compounds (VOCs) and smoke particles. 

If you’re comparing air purifiers vs. HVAC filters, you would need the highest rating of MERV filter to achieve the equivalent.

Depending on the make and model of an air purifier, you may be able to find one that will stop particles as small as .01 microns. 

A MERV 16 HVAC filter will only stop particles at a minimum of .3 microns. 

Anything denser than this—like a HEPA filter—will impede airflow and potentially destroy your HVAC system.

This point alone indicates there is a clear winner in the air purifier vs. HVAC filter debate—depending on the air purifier.

Air Purifier Versus HVAC Filter: Aesthetics & Noise

This may be irrelevant to some people, but your HVAC filter is hidden away at the air handler of your HVAC system. 

An air purifier is out in the open and will take up floor space.

Like any other portable HVAC appliance, you will hear your air purifier running. 

An HVAC filter will not add any additional noise to your living space.

The Benefits of an Air Purifier

Keep in mind we’re not comparing apples to apples.

There’s a good chance that an air purifier will do a better job killing germs, bacteria, mold, and a selection of viruses.

This isn’t to say that an HVAC filter isn’t capable of doing these things, but remember, a filter merely catches and holds particles. 

Depending on the model, an air purifier goes a step further. 

It sanitizes your air by killing germs, bacteria, and mold.

This means cleaner air and fewer respiratory issues for you and your family.

Air Purifier vs HVAC Filter: Conclusion

In many cases, an air purifier is the better choice if you’re considering an air purifier vs. an HVAC filter. 

This assumes your HVAC system can’t handle a very dense filter.

And the condition of your home and the needs of your family call for something that will filter out a wider variety and size of pollutants.

Remember that all air purifiers are not created equal when doing your research. 

If you or your family have allergies or asthma, select something that will do more than contain pollutants—it will also kill them.