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

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?

HVAC-air-filters-industry-page-indoor-air-Allergy-StandardsOur 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


air filters, HVAC, furnace filters, science, testing, Certification Program, asthma, allergy, allergy insights, healthier home, indoor air quality, indoor environment

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By |2023-12-13T16:31:06+00:006 November 2019|Tags: , , , |Comments Off on Why and how we certify HVAC and furnace filters – a Q&A