Fiberglass vs. Pleated Filters: Which Type of Furnace Filter is the Best? | HowtoHome

Fiberglass vs. Pleated Filters: Which Type of Furnace Filter is the Best?

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Fiberglass vs. Pleated Filters: Which Type of Furnace Filter is the Best?

When it comes to maintaining a furnace, filters are one of the most basic ways to do so and improve the indoor air quality. They are essential to the furnace’s operation and are the most important part of its maintenance. Filters trap airborne particles and keep them from clogging different components of the unit. Pollutants such as grime, dust, and other debris can build up and hinder the unit’s ability to function efficiently. Buildup also causes the unit to work harder, increasing the amount of energy used to operate the system.

There are several different types of filters on the market with various features, such as fiberglass air filters, fiberglass furnace filters, electrostatic air filters, and HEPA filters to ensure high efficiency in the filtration process. All filters have a MERV rating (Minimum Efficiency Rating Value). This rating determines how well the filter will capture pollutants. The MERV rating scale ranges from one to 20. The higher the MERV rating is, the more effective the filter is at trapping airborne pollutants in a room.

There are various types of filters on the market with different features—offering a wide array of benefits. Different types of filters include fiberglass/synthetic filters, polyester filters, pleated filters, electrostatic filters, reusable filters, disposable filters, and HEPA filters. Fiberglass and pleated filters are among the less inexpensive filters and are very common in most HVAC systems for residences and offices.

Fiberglass Filters


Fiberglass filters typically have a MERV rating between 2 and 4. They are one of the most common types of filters found in a furnace. The filter is made from spun fiberglass and is one inch thick. These filters last around 30 days before they need to be replaced for maximum efficiency. They trap dust and keep it from clogging various components of the furnace. They are effective at capturing other large airborne particles such as lint and even small insects. In terms of air quality and trapping other airborne pollutants, fiberglass filters are not the best option and will not remove small toxins from the air.

Due to fiberglass filters lasting for a short amount of time, they are not built to be sturdy. It is common for the filters to have some sort of metal reinforcement depending on the brand and filter model. The metal reinforcements allow the filter to be less flimsy.

Pleated Filters


Pleated filters are made how the name suggests: folded into pleats and this provides the filter with good air flow. Having pleated material also increases the surface area of the filter. Pleated filters have various depth sizes, ranging from one to six inches in depth. The most common pleated filter depth for an HVAC system is one to two inches. They have a MERV rating between nine and 12.

Unlike fiberglass filters which only remove large airborne pollutants such as dust, lint, and small insects; the pleated filter can remove dust, mites, pet dander, pollen, mold spores, and even bacteria, which means that aside from protecting the HVAC unit, the pleated filter is also improving air quality. Improved air quality is beneficial for consumers with respiratory issues and allergies.

Some pleated filters may be manufactured with a wire mesh on one side which is a red flag for a cheaply made filter. The filter should be made from materials that do not require wire mesh to maintain the shape and prevent blockage; it should be able to do all that on its own. As long as models with wire meshing are avoided, the quality and effectiveness of the pleated filter will still be higher than the fiberglass filter. The suggested time to replace pleated filters is every three months, with monthly checks to ensure there are no blockages.

Factoring Cost


When it comes to the cost of a fiberglass filter versus a pleated filter, they are both relatively cheap. The pleated filter does cost a bit more. If budgeting comes down to the dollar, in most cases, it is cheaper to buy pleated filters over fiberglass filters. Fiberglass filters are recommended to be changed every 30 days whereas pleated filters only need to be changed every 90 days. Depending on the price of each filter (per brand/model), pleated filters will cost less annually due to requiring fewer replacements. If the recommendations are followed, fiberglass filters will be changed 12 times a year, and pleated filters will be changed only four times per year.          

Which Filter is Best?


In accordance with the MERV scale, pleated filters are better than fiberglass filters. Whereas fiberglass filters fall at the lowest ratings, pleated filters range from medium to high on the MERV scale. Pleated filters also help improve the air quality and trap more pollutants. If there are no respiratory issues or allergies present in residents, fiberglass filters are a good, cheap option if a quick change is needed.

Where to Find Fiberglass and Pleated Air Filters


Fiberglass filters are the most typical filters found in most HVAC systems, as previously mentioned. Pleated filters are also quite common and are preferable for cleaner air. There are plenty of different filter brands and models to choose from on the market. The Internet is a great source for sifting through several choices and purchasing the right one.


Flanders Flat Panel E-Z Flow Heavy-Duty Air Filter

The Flanders Flat Panel E-Z Flow Heavy-Duty Air Filter has earned itself 4.4 stars out of 5 on the Amazon website. There are plenty of sizes available and the filter comes in a 12 pack. The filters have a MERV rating of 4 and trap particles such as dust, pollen, and lint. The clipboard design of the filter protects the corners from separating, and the double-sided metal retainer reinforces the frame, adding durability and strength. The filter itself is made from filament-spun glass (fiberglass).

It is recommended to change the filter every month. Some consumers can stretch this out to a few months depending on their specific HVAC system. Any type of filter can last longer than the recommended time frame if it is not in bad condition. One verified purchaser reported that they were able to get between three and four months of use from one filter. Always check the filter after 30 days and then frequently after that if not changed.


The Flanders Flat Panel E-Z Flow Heavy Duty Air Filter can be found here for around $.


Nordic Pure Pleated Air Filter

The Nordic Pure Pleated Air Filter has earned itself a high rating of 4.5 stars out of 5 on the Amazon website. There are multiple sizes to choose from and the filter comes in a pack of six. The Nordic Pure Pleated Air Filter is pleated with hypoallergenic/antimicrobial, electrostatic material. It captures large airborne pollutants such as dust, mold spores, pet dander, pollen, lint, and some bacteria.

The filter has a MERV rating of 8. According to the manufacturer, this air filter’s MERV rating means it is high enough to efficiently trap large particles, but at the same time is low enough to reduce any strain on the system. The less strain that is on an HVAC unit, the less energy that is produced. This is great for the electricity bill and the environment.


Find the six pack the Nordic Pure Pleated Air Filter here for around $