The Difference Between Fibreglass Filters And Electrostatic Pleated Air Filters

Question: Pardon my ignorance…Thank goodness for folks like you!! I just purchased a top-of-the-line Trane unit.  I did not realize there are so many different types of filters. In my old unit, I used cheap fibreglass filters - not knowing that was a mistake (however my old Trane ran for 17 years +, with less than $300 in repairs that entire time-period, and no annual maintenance.) With this new unit, what should I use, or let me ask like this… Is a Nordic Pure or 3M Filtrete Micro-Particle Reduction Filter 700 alright to use? Both filters are one inch thick but the Filtrete filter doesn’t have a MERV rating on it.

Let me start by saying that in my opinion Trane is one of the top residential air conditioner and heat pump manufacturers. Their equipment performs well and usually operates trouble free. Although, I would consider 17 years of trouble free service with less than $300 in repairs to be exceptional.

The only thing I consider to be more important than a quality product is the quality of the installation. This is far more important. The best equipment installed inadequately will not perform as well as equipment of lower quality that is installed properly.

What is the difference between fibreglass filters and Nordic Pure or Filtrete filters?


Fibreglass filters were originally designed to prevent things from getting into your furnace or air conditioning system and causing problems with fans, pulleys and other components. They were not designed to improve indoor air quality.

Nordic Pure and Filtrete filters do both. They improve indoor air quality by attracting and capturing allergy causing micro particles, and help keep your equipment clean. Air in your home is continually re-circulated through these filters, and is cleaned each it passes through the filter.

What does electrostatic mean?

These pleated electrostatic filters are made with positive and negative charged media fibres. Particles in the air passing through the filter will be either positively or negatively charged and result in the charged particles sticking to the filter.


Are Nordic Pure pleated air filters antimicrobial?

From their website:

Nordic-Pure-Filter

How often do I need to change pleated air filters?


These filters should be changed every three months. However, the effectiveness and life of the filter will vary depending on the individual conditions in your home. A dirty duct system, construction, pets, smokers and running the fan continuously are some of the things that can shorten the life of your filter.

In these cases, the filter should be checked more frequently and changed if needed. For the untrained eye it can be difficult to determine if the filter is dirty enough to change or not, an air filter change indicator installed on your air handler can help with this.

Do I have to worry about restricted air flow with these filters?


These pleated air filters are designed to operate in most residential furnaces and air conditioning systems. If the filter remains in use longer than three months, it may begin to restrict airflow or cause operating problems.

Compare pleated air filters

Compare Filtrete and Nordic Pure pleated air filters

Question: I would like to save costs by getting a washable air filter, but it seems that none of them can get a MERV over 8, and I’d like something with a MREV of 11 or higher since we have allregies in the family.  How does Boair or air-care-filters.com filters compare to the filtrete ultra allergen. If I need to get a disposable, is the Nordic the best priced disposable filter?

You are correct about washable filters. Although they don’t have MERV ratings they perform close to a MERV 8. Although washable filters have their own positive characteristics, if allergies are a concern for you I would recommend high efficiency pleated air filters.

I did some quick investigating and this is what I found when comparing these pleated air filters

- Filtrete Ultra Allergen filters are $13.88 at Walmart and they have a MERV rating of 11 (I used Walmart because they usually have good prices)

- Nordic Pure Box of 6 is $48.97 which works out to $8.16 each and they have a MERV rating of 12

Both of these pleated air filters enhance the performance of their filters electrostaticly.

Nordic Pure and Filtrete filters don’t support the growth of bacteria, fungi, mildew or mold.

Nordic Pure filters have a higher MERV rating and they are much less expensive than Filtrete Ultra Allergen filters.