HVAC Filters

HVAC Filters2019-11-04T11:26:03+00:00

HVAC Filters

On average, people spend up to 90% of their time indoors, and indoor air can be two and a half times as polluted as outdoor air.

Indoor Air Quality is of particular concern for those affected by asthma and allergies, but a healthier home is of broader benefit to all.

The asthma & allergy friendly® Certification Program seeks to assist people to identify products which will make a genuine difference to their indoor environment. It develops certification standards for relevant categories of products, and all certified products undergo testing to those standards. In this way, the consumer can then make an informed choice about materials like insulation, flooring products, etc. that they bring into their home.

In the case of HVAC filters, we test the product in an environmentally-controlled test duct, using test dust that contains allergens. It is important that the filter can remove allergens from the air. Different allergens respond differently to filtration, because they have different sizes and features. Our standard addresses these issues. We also test the filter when it is loaded with dust, to make sure its performance is maintained.

Our HVAC filter standard is one of 46 standards in the asthma & allergy friendly® Certification Program, covering appliances, bedding products, air filters, building products, and services that can have an impact on the indoor air environment. You can explore the HVAC filter standard in more detail using the menu on the left, or use the links above to explore other standards.

Brand Promises for Healthier Home: An Interview with 3M

It’s no secret that consumers are demanding products that are safer and healthier for themselves and their families. But many brands are capitalizing on this by making health claims that are scientifically unfounded. What separates the companies that are delivering on their brand promise from the ones that are not, and how can companies tighten their messaging to cut across the noise?

Here, Allergy Standards’ VP of Business Development, Courtney Sunna, interviews leaders, brand managers, and marketers who are part of a global movement towards healthier products that are rooted in rigorous science. In this interview, meet Carrie Sazama, Senior Brand Manager at 3M, who helps breathe new life and fresh ideas into home air filters for one of the world’s most innovative companies.

Courtney Sunna: Consumers are constantly bombarded with everyday “dangers” to be wary of. Is poor indoor air quality really that big of a threat?

Carrie Sazama: Consumers should certainly be aware of indoor air quality! The U.S. Environmental Protection Agency (EPA) has ranked indoor air pollution among the top five environmental risks to public health. With Americans spending, on average, nearly 90% of their time indoors, it’s never been a better time to start caring about your indoor air quality. Yet awareness of poor indoor air, its risks and common causes, and simple ways to improve it are alarmingly low.

Even well-maintained and ventilated homes may have dust, pollen, mold spores, bacteria, and other viruses in its air.

Choosing the right filter is one simple way to help improve your home’s indoor air quality. While you can’t always see unwanted airborne particles, Filtrete® Healthy Living filters use exclusive 3-in-1 technology from 3M to pull in and trap unwanted particles, while letting cleaner air flow through.


Courtney: Why are third-party Certification Marks important for your brand?

Carrie: Filtrete Brand’s team of scientists continuously seek ways to innovate the category with cutting-edge technology.

In addition, the brand frequently conducts internal and independent testing – like the asthma & allergy friendly® Certification Program – to ensure the products meet high standards and evolving consumer needs.

Having third-party certification marks helps give the consumer peace of mind that they are taking a proactive step to help reduce airborne allergens from the air passing through their home’s filter.


Courtney: How is Filtrete® Brand helping consumers become more engaged with the quality of their indoor air?

Carrie: To help consumers take control of their home’s air, Filtrete® Brand is launching the Smart Air Filter, the first-ever Bluetooth®-enabled HVAC air filter. When paired with the Filtrete® Smart App, it’s designed to remind you when it’s time to replace your filter, provide helpful tips on how to improve indoor air quality, show outdoor air quality conditions, and more.

People with pets, asthma, allergies, and/or respiratory issues have more specific air quality considerations to keep in mind. The new Filtrete® Smart App takes these factors into account and bases data-driven tips and alerts accordingly.

Filtrete® Smart Air Filters will be available at participating retailers in spring 2018.


Courtney: How do you focus on building long-term trust and loyalty with consumers?

Carrie: For more than 25 years, Filtrete® Filters have delivered cleaner air to millions of homes. Helping people get cleaner air for themselves and their family is our top priority. Because every breath is important, the Filtrete® Brand created Filtrete® 365 to help people get smart about their home environment through personally-relevant insights. The Filtrete 365 Program’s goals are to help people choose the correct filter while also strengthening brand loyalty through the distribution of personalized content. Filtrete 365 also sends custom filter change reminders, through both SMS and email, based on their lifestyle and weather in their area. Filtrete® is committed to helping you create a cleaner, healthier, and fresher home environment.


Courtney: Thank you. 


About 3M Filtrete: For nearly 25 years, Filtrete Brand has been helping homeowners make every breath count by delivering cleaner air to millions of homes. Developed by 3M scientists and engineers, Filtrete Electrostatic Air Filters are designed with exclusive Filtrete Brand 3-in-1 technology from 3M that pulls in and traps unwanted particles — such as dust, pollen, mold spores, bacteria and viruses — while letting cleaner air flow through. Filtrete Filters are consistently rated highly by a leading magazine that rates consumer products.

Standard Abstract : Air Filters

Air Cleaners that are Certified asthma & allergy friendly® are tested to the ASP:08-01 Air Cleaner Certification Standard. The Certification Standard utilizes an algorithm of proprietary and recognized scientific techniques to assess Air Cleaners for their ability to reduce allergenic and irritant materials. Submitted Air Cleaner models that pass certification testing are granted a certificate stating that the particular Air Cleaner meets the requirements for the asthma & allergy friendly® ASP:08-01 Certification Standard.

Allergy Standards Ltd (ASL) subjects the Air Cleaner to allergen measure based performance testing to ensure that the Air Cleaner reduces total allergen burden that remains airborne. Assessment for certification requires that the Air Cleaner be evaluated in terms of indoor allergen levels that are representative of those found in both air and surface samples of typical homes. The asthma & allergy friendly® Certification mark is awarded to those air cleaning products that have been scientifically demonstrated to contribute to the goals of allergen reduction.

Part 1: Effective airborne allergen removal

For each of the allergen test conditions, the reduction of allergen must be at least 75% lower than the natural decay under that condition.




Pass/Fail Criteria



Removal of airborne allergen


Demonstrable for one or more of the allergens tested


Part 2: Effective retention of allergen




Pass/Fail Criteria

Retention of removed allergen within the air cleaner (recovered from filter media)



Part 3: Types of air cleaners assessed

Media based air cleaners alone are considered in this protocol number, while other technologies are not eligible for certification under this standard.

Part 4: Ozone 

The Code of Federal Regulations (CFR) section 21:801.415 requiring ozone exposure at less than 0.1 mg/m3must be achieved.

All CERTIFIED asthma & allergy friendly® paints are associated with a unique Certification code.

Why and how we certify HVAC and furnace filters – a Q&A

There is ever-increasing awareness of the chemicals and allergens we come into contact with every day, particularly if you or a member of your family has asthma or allergies. We created the asthma & allergy friendly® Certification Program to help you improve your indoor environment by identifying products and services that can help to reduce allergens and create a healthier home environment.

But what is it that makes some HVAC/furnace filters better for the indoor environment than others, and where do we draw the line to decide to certify a HVAC/furnace filter as asthma & allergy friendly® ? We hope that the questions below will clarify this. Let us know if you have more questions!

Why do we certify HVAC and furnace filters?

Our goal in the asthma & allergy friendly® Certification Program is to create a healthier indoor environment for you and your family, as well as to reduce allergens in the home. So we look at all elements of the indoor air environment.

Heating, ventilation, and air conditioning (HVAC) and furnace filters are important elements of climate control in homes. These systems are mostly used to regulate temperature in the home, and sometimes also humidity. They work by forcing air through ducts to move it throughout the home.

Because of this movement of air, it is also possible for these systems to transport allergens and other small air particles throughout the home. Pollens, mold spores, and animal dander can all be spread through the home in this manner. So having effective filtration of the air passing through a climate control system is very important in maintaining a healthy indoor environment.

How do we test HVAC/furnace filters?

We use a standardised test duct to test these filters. This is a controlled duct where the filter can be inserted at the centre, and air can be forced through it. We can introduce dust containing allergens in the ‘upstream’ part of the duct. This air is then pressed through the filter, and we can test the ‘downstream’ area past the filter to see how much allergen and dust has passed through the filter.

1. Removal of Allergen

We introduce a specific amount of test dust that contains pollen, house dust mite allergen, and cat allergen into the test duct, and a blower forces the dusty air through the filter. When the air passes through the filter, we test it on the other side to see how much of the dust and the allergen passed through. We require that at least 95% of the pollen is captured by the filter, at least 92.5% of the house dust mite allergen, and at least 85% of the cat allergen. The difference between these numbers is because cat allergen particles are the smallest of the three allergens, and pollen is the largest. We also measure the tiny micro-particles in the dust, and make sure that at least 50% of them are removed by the filter.

2. Seals

The centre of your filter can be the best filter in the world, but if the seals around the edge are weak then the air and allergen can pass around the filter and be spread throughout the home. To test this, we cover the filter media with an impermeable film. We then insert the filter in the test duct, and challenge it with pressurised air to see whether the air passes around the impermeable filter. We make sure that the air by-pass is less than 10% in 30 seconds.

3. Loaded Performance

It isn’t enough to only test a brand-new filter and check if it can remove allergens and small particles. Over time, dust can build up on a filter, which is why you need to change it every so often. But before that, it is important that even when it is loaded with dust the filter can still perform well. We challenge the filter with twice the typical dust load that would be expected in a home in a three-month period. We record the filter flow and the air pressure in the test duct before and after the filter. We make sure that the performance of a loaded does not drop by more than 20% compared to a fresh filter.

How often should you change your HVAC/furnace filter?

You should follow the manufacturer’s instructions for changing the filter. When a filter is certified asthma & allergy friendly®, we have determined the best frequency for changing the filter, to make sure that its performance won’t drop and that you can be sure it is still filtering the air properly. This frequency will be in the filter instructions.

What else do we certify?

We have 46 different asthma & allergy friendly® certification standards for products and services, addressing all areas of the indoor air environment. Some of these relate to products which remove allergens and dust from the indoor environment, like vacuum cleaners, air cleaners, dehumidifiers, and washing machines. Some of them relate to products where it is important not to provide an easy home for allergens and that it is possible to remove allergen from them – like bedding, toys, and flooring. And some of them relate to household products that should make as little an impact on the indoor environment as possible – like flooring and paint.

You can find out which products are certified asthma & allergy friendly® and read more here: www.asthmaandallergyfriendly.com


How To Take Care Of Our Indoor Air?

Maybe you live in the city, maybe you have a family member with asthma or other respiratory issue, maybe you have just realised how polluted our indoor air is and want to live in a healthier home. Whatever the reason, you have come to the conclusion that you need an air purifier. Or, wait, is it an air cleaner you need? What about an air filter?

It’s a minefield out there when it comes to the terminology, technology, effectiveness and variety of models that you can choose from. How do you know what’s right for you? Let me try to simplify a few things for you.

What’s in a Name?

Most manufacturers use the terms air cleaners and air purifiers interchangeably. Some refer to air cleaners as the products with a HEPA filter and purifiers as those that use Ultra Violet light, negative ions or ozone to clean the air. Often the devices use a combination of these with the ultimate goal of removing pollution- particles and gases – from the air.

So, the technologies available are:

1. HEPA Air Filter

Simply put, this is a fine mesh with flaps folded bit like an accordion, that traps particles as air is pushed through it by a fan. It can trap 99.97% of particles 0.03microns or larger. That includes pollen spores, pet dander, dust mites and some bacteria. This is a great option if you have an allergy sufferer in the house.

There is a bit of maintenance involved in that the filter has to be changed every two to three months or its effectiveness deteriorates. Some devices have a helpful indicator to remind you that the filter needs changing. Most HEPA filters also have a prefilter that removes larger particles and prolongs the life of the HEPA filter.

On the down side, a HEPA filter will not remove odours, chemicals or gases. For that you will need an activated carbon filter.

2. Activated Carbon filter

Interestingly, one of the first applications of activated carbon was to clean dirty water in the early 1900s. Subsequently it was used in gas masks to protect soldiers from poisonous gas in World War 1. 

When carbon is activated it becomes porous like a sponge, creating tiny holes within the carbon where pollutants get stuck, never to be released. All sorts of problematic pollutants can be trapped by carbon – bad odours, chemicals, smoke – so they are particularly useful for people sensitive to poor air quality. For instance, those nasty VOCs that are released by new furniture, cleaning products or paints are eliminated nicely by activated carbon.

Maintenance is necessary and depends on the thickness of the filter as well as the nature of the pollutants. If cigarette smoke is the main pollutant, for example, the filter gets saturated faster and will need more regular changing.

Because a carbon filter isn’t especially effective at trapping particulate matter, they are often combined with a HEPA filter.

3. Ultraviolet Sterilisation

A UV sterilizer uses the same UVA and UVB rays emitted by the sun to kill moulds, bacteria and even some viruses. A UV purifier can work well in the kitchen or bathroom, where the heaviest bacterial load is.

4. Ionic or Electrostatic

These technologies have become a bit controversial as some may generate ozone. Ozone is harmless in small amounts but it’s crucial that you check how much a device produces as, if inhaled in large amounts it can be damaging, especially to the very young, the very old or those with respiratory illness. Avoid anything that creates more than 50-60 parts per billion. Look for certification marks for reassurance that your device is safe. 

These purifiers work by producing negatively charged oxygen atoms which combine with dust, pollen or any positively charged ion and bonds with them. The resulting heavier particle then falls to the ground or, depending on the type of device, is trapped on a special collection plate. An ioniser therefore doesn’t eliminate or absorb the contaminants and so there is the potential problem of the particles becoming loose and re-entering the circulation.

An advantage of this type of purifier is that there is no filter and therefore no maintenance cost. If there is an ioniser plate, then this can simply be wiped clean and reused. This should generally done about once a week. These devices work against the smallest of particles including dust, pollen, bacteria and pet dander. They also tend to be low cost.


Size and Positioning Matters

Sick building syndrome Indoor Air Quality Allergy StandardsWhile it may be tempting to invest in the less expensive devices, think first of your problem and your goal. A single activated carbon purifier may be the best solution for a smelly utility room but if your aim is to reduce allergy triggers for your family, then you must factor in your whole house. My kids typically throw their worn clothes on their bed (bedrobe!) or the floor (floordrobe!) so any pollen tracked in from outside is disseminated throughout the house. When we walk around, we stir up dust which then travels just about anywhere.

A single purifier will only clean adjacent rooms not connected by a door or wall. We spend most of our time in the kitchen, living room, bedroom, office and basement, so consider each individual room’s problems and its occupants before choosing the right device. Positioning can improve the function too- if its cigarette smoke, position your purifier where the ashtrays are. A purifier by the door can help filter air as it comes into the room. In general, keep the device in a place with high air flow to maximise efficiency.

Finally, in a living area where people are continuously coming and going a purifier must be keptrunning 24/7. In a room like a bedroom or office where the door can be kept closed, then it’s only necessary to run the machine when the room is occupied.

Medical & Lifestyle Author Dr Anna O'Donovan

Medical & Lifestyle Author Dr Anna O’Donovan

About Dr. Anna O’Donovan – Medical & Lifestyle Author

Anna is a mum of three children, one with allergies, and she suffers from allergies and asthma herself. She is a qualified doctor and worked as a General Practitioner and as a dentist for a number of years. She is also an award-winning author.


air care, indoor air, asthma, asthma triggers, allergy, allergy triggers, healthier home, HEPA, air cleaner, air purifier, air filter

Further Reading 

Air Purifier Maintenance, Sylvane, Click Here

Air Purifiers: The Good, The Bad, and the Ugly. Click here

8 Best Air Purifiers For Your Home, Forbes, Click here

Related Internal Links


Content in development. 

Certification Nameasthma & allergy friendly®ASHRAE – MERV RatingAmerican Lung Association
Certification Logo

american lung association fighting for air health partner
Effective airborne allergen removal
Reduce total allergen burden by removal of allergen from the air





Evaluation of loading
As the filter becomes loaded with particulate allergen the air flow may decrease, adversely impacting on performance and increasing energy consumption
Evaluation of seals
The seals at the edges of the filter are strong enough that air (and also particles) don’t go around the edges

Other criteria
Certifications are mapped against

asthma & allergy friendly®

but may include other criteria

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