Want cleaner air in your house? Consider getting an air purifier. But once you start looking for air purifiers, you’ll run into one decision pretty quickly: HEPA filters or carbon filters?
Both HEPA and carbon filters are common. Both are effective. But they serve very different functions. Let’s explore the difference so you can decide which filter you need.
What Is a HEPA Filter?
HEPA stands for High Efficiency Particulate Air. It is a paper filter made up of extremely small fibers woven together. These fibers capture particles out of the air before they can be inhaled.
Filters must remove 99.97% of particles that are 0.3 microns in diameter to be considered “True HEPA.” To give you some perspective, that’s far smaller than the average human hair, which is 70 microns.
HEPA filters excel at trapping:
- Dust and dust mites
- Pet dander
- Pollen
- Mold spores
- Smoke particles
- Some viruses
If you have allergies or asthma, a HEPA filter may greatly improve your air quality. HEPA filters physically trap particles, so they won’t recirculate throughout your home. This is why HEPA filtration has remained the standard for so long.
Beware of filters that claim to be “HEPA-type” or “HEPA-like.” These cheaper alternatives will not meet true HEPA standards. Look for “True HEPA” if you want the real thing.
What Is a Carbon Filter?
Carbon filters work differently than HEPA filters. Rather than trapping particles in your air, carbon filters absorb unwanted gases and smells.
Carbon filters use an activated carbon filter. This filter is made of carbon that has been treated to be extremely porous. This creates billions of tiny pockets for gases and chemicals to stick to.
Carbon filters can handle:
- VOCs (“volatile organic compounds”)
- Smoke odors
- Cooking smells
- Pet odors
- Chemical residue from cleaning products
- Formaldehyde
VOCs are gases emitted by a wide variety of products like paint, furniture, and even many common household cleaners. While you can’t see them, they may cause irritation and health problems. Carbon filters can reduce VOC levels in your home.
Got something frying on the stove? Smoke indoors? Live close to a freeway? A carbon filter can help. Where HEPA filters can’t reach, carbon filters will.
The Difference Between HEPA and Carbon Filters
Here’s the simple version:
- HEPA filters trap particles.
- Carbon filters absorb gases and odors.
HEPA filters and carbon filters remove different types of pollutants from your air. A HEPA filter won’t do anything for cooking odors, but a carbon filter will. That’s why some air purifiers have both!
When to Use a HEPA Filter
Get a HEPA filter if you are mostly concerned with:
- Allergies/hay fever
- Asthma/lung function
- Pet hair/dander
- Dust collecting on surfaces
- Mold spores
Someone with asthma will benefit the most from True HEPA filtration. Sleeping with a HEPA air purifier on can help lessen your allergy symptoms at night. It can also work wonders when seasonal pollen is high or if wildfires have blown through your area.
When to Use a Carbon Filter
Get a carbon filter if your problems are mostly:
- Cooking smells/food odors
- Smoke (candles, cigarettes)
- Pet smells
- Chemical smells from new furniture/paint
- Fumes from cleaners
Carbon filters work through a process called adsorption. Pollutant molecules adhere to the carbon filter and are trapped there. Eventually the filter becomes saturated and will need to be replaced.
Take note: Not all carbon filters are created equal. Some air purifiers contain a thin sheet of carbon that provides minimal benefit. When in doubt, look for ones with large amounts of powdered activated carbon.
Why Do Some Air Purifiers Have Both?
The best part is that you don’t always have to choose between HEPA and carbon. Many of the best air purifiers use both filter types.
These filters are typically arranged in stages:
1. Air enters the purifier
2. Pre-filter catches large particles (hair, lint)
3. HEPA filter traps smaller particles
4. Carbon filter absorbs gases/smells
5. Clean air returns to the room
By combining filter types, you get complete coverage. You can breathe easy knowing your air purifier traps particles and absorbs gases & odors. It’s a no-brainer for most applications!
Things to Consider
Before you go out and buy an air purifier, take a moment to consider your needs. Here are a couple things to think about:
Room Size
Does the purifier have enough power to clean your room? Don’t purchase a purifier that isn’t meant to cover the square footage you need. It won’t effectively clean your air.
Filter Replacement Costs
HEPA filters and carbon filters aren’t permanent. Check how often filters need to be replaced and how much they cost. Add this to the overall price of the air purifier.
Noise Levels
Ideally, you’ll leave your air purifier on at all times. Find purifiers with a low nighttime setting if you plan to use it in your bedroom.
Air Quality Sensors
Some air purifiers come with sensors that monitor your air quality. These sensors can alert you when air purification is needed.
Check for Certifications
Hopefully the company you buy your air purifier from is honest about its filtration capabilities. If not, look for third-party certifications from AHAM or Energy Star.
HEPA Filter or Carbon Filter?
Neither type of filter is better than the other. It all depends on what you need.
Deal with allergies, asthma, and dust? Get a True HEPA filter. Troubled by odors, smoke, or VOCs? Get a carbon filter. Still can’t decide? Grab a purifier that has both filters!
The right air purifier for you has the filter that will eliminate your specific air quality concerns. Identify your problem and do what works best for you. A breath of fresh air is always worth the investment.
Real World Example of How Matching Air Purifier to Odor and Particle Problem
Helped Improve Home’s Indoor Air Quality. A California homeowner dealt with chronic indoor air quality problems for years. Their house always smelled like cooking odors and dog smells. Additionally, several members of the household suffered from allergy symptoms like sneezing, itchy eyes and congestion.
They initially bought a cheap air purifier with only HEPA filtration. Although dust, pollen and pet dander floating around in the air became minimized, the odors and chemicals never fully dissipated.
When they upgraded to an air purifier with multiple stages of filtration (True HEPA plus a thick activated carbon filter), they noticed a big difference. Cooking smells didn’t linger as long, the air smelled fresher and allergy symptoms were greatly reduced within weeks.
The HEPA filter was doing its job of trapping microscopic particles like dust mites, pollen and mold spores. But without an activated carbon filter to absorb VOCs, smoke residue and household odors, they were free to bounce around the house unchecked.
This story illustrates a point many consumers don’t realize – particle filtration and odor elimination are two totally separate processes. In many cases, the right air purifier for your needs will have both technologies working together for maximum indoor air purification.
Frequently Asked Questions About HEPA and Carbon Filters
Which is better: HEPA filter or carbon filter?
They both have their benefits – there is not necessarily a “better” option. When it comes to air cleaners, HEPA filters tackle particles like dust, pollen and pet dander floating in the air. Carbon filters take care of smells like odors, smoke and harmful gases such as VOCs.
Do HEPA filters get rid of odors?
No. HEPA filters are designed to remove particles in the air, not odors or gases. Think of them as great at trapping dust, pollen and pet dander, but incapable of absorbing cooking smells, cigarette smoke odors or chemical fumes. This is where carbon filters are essential.
What does a carbon filter do in an air purifier?
Also known as an activated carbon filter, these filter out VOCs, smoke smells, pet odors, cooking odors, chemical gases and other airborne pollutants that cause unwanted indoor smells.
Are HEPA air purifiers effective for allergies?
Absolutely. True HEPA air purifiers are one of the most effective ways to capture allergens like pollen, dust mites, mold and pet dander before they spread throughout your living space.
Can air purifiers help with asthma?
If someone in your home suffers from asthma, an air purifier with a True HEPA filter may be able to lessen asthma triggers. By removing tiny particles and allergens from your indoor air, asthma sufferers may breathe easier and experience less irritation.
Should I get an air purifier with both HEPA and carbon filters?
Yes, most people will benefit from an air purifier that includes both HEPA filtration and activated carbon filtration. This way you can target and eliminate both indoor particles and odors/chemical pollutants.
How long do HEPA and carbon filters last?
Every household is different based on how often you use your air purifier and the overall air quality in your home. A good rule of thumb is that most HEPA filters need to be replaced every 6-12 months. Carbon filters may need to be replaced more frequently if you regularly encounter smoke, cooking smells and VOCs.
What are VOC’s found in indoor air?
VOCs are gases emitted from paint, furniture, cleaning products, adhesives, and flooring. Long-term exposure to VOCs can have a negative effect on your indoor air quality and health.
Can air purifiers remove smoke?
Yes! Air purifiers with True HEPA filters will remove smoke particles from the air. But if you want to eliminate smoke odors and gases, you need an air purifier with a sizable activated carbon filter as well.
Are all HEPA filters created equal?
No. Unfortunately there are many products out there that use terms like “HEPA-type”, “True HEPA-type” or “HEPA-like”. These do not meet certification standards for True HEPA filtration. True HEPA filters are required to remove 99.97% of particles that are .3 microns in size.
How do I know what size air purifier I need?
Make sure you get an air purifier that is meant for the room size you intend to use it in. Purifiers that are too small for a space simply won’t circulate or clean the air properly.
Are air purifiers worth buying?
If allergies, asthma, pet smells, smoke, dust or general poor indoor air quality is an issue in your home, we think air purifiers are worth it. Many people notice improved sleep quality, easier breathing and less allergy symptoms after regularly using an air purifier.
