What Is a Furnace Filter and Why Do You Need One?

Have you ever experienced respiratory issues due to dust and smoke in your home? Perhaps that might be due to your home’s furnace and its filter.

Do you use a furnace for keeping yourself warm at your home? If yes, you belong to the vast majority of Americans who use a furnace in their homes. There are a lot of cold regions in America where the temperature falls to near zero. In 2018, the furnace industry in America had a revenue of 115 billion dollars! If you are new to furnaces, you might ask: what is a furnace filter?

A furnace filter is an essential part of a furnace, the primary function or purpose of this filter is to keep the furnace and the blower fan safe. This filter prevents impurities such as hair, dust, germs, debris, and other types of pollutants from entering the furnace. Such impurities often clog the furnace and cause it to malfunction.

What Does A Furnace Filter Do?

A furnace filter maintains the indoor air quality (IAQ) so that you can breathe in good quality of air. People that suffer from respiratory issues and problems find a furnace very useful, apart from using it as a heater.

How Does A Furnace Filter Work?

A furnace gathers up the cold air from outside through its return ducts. The air from outside reaches the furnace through these return ducts. Then inside the furnace, this cold air is heated with the help of a heat exchanger. After heating the air, hot air travels through the vents to different rooms and sections inside your home.

The hot air settles down quickly due to the fact that the cold air present inside your room rises. This cold air also carries the dust, debris, hair, and so on with itself back to the vents. Then this air passes through the furnace filter, and it filters this air removing most of the impurities from it. The furnace filter stops the air from entering the system and reaching all your rooms.

4 Types Of Furnace Filters

You will find furnace filters made from different quality materials and substances. Other materials have a unique impact on the air, and you can choose the furnace filter that suits your requirements. Furnace filters are either permanent or disposable. You must regularly replace disposable furnace filters after a fixed time, whereas you would require cleaning and maintaining a permanent furnace filter at regular intervals. See also: Washable Furnace Air Filter vs. Disposable Filter: Which is Better for You?

Fiberglass Furnace Filter

This type of furnace filter is capable of stopping more significant impurities and debris present in the air. It will not massively impact the indoor air quality of your homes. If you suffer from respiratory conditions such as asthma or any other issue, you should opt for a different furnace filter.

A fiberglass furnace filter is disposable, which means you will have to change or replace this furnace filter every month. If you are on a confined budget, this furnace filter is ideal for you as it is the least expensive and the most commonly used filter.

Pleated Furnace Filter

Manufacturers mix cotton paper and polyester to make pleated furnace filters. This furnace filter can catch small impurity particles such as dust, spores, and mites due to its unique composition. For improving the indoor air quality index of your home, you can use this furnace filter.

Pleated furnace filters are also disposable, just like fiberglass furnace filters. As these filters are disposable, they are cheap, but you have to change them regularly. This type of filter is also environmentally friendly and safe to use.

Electrostatic Furnace Filter

Electrostatic furnace filters use a combination of special electrostatic paper and cotton fibers. These furnace filters can catch and prevent small particles present in the air from entering the furnace system. You must buy this type of furnace filter if you have a smoker or pet in your home.

Electrostatic furnace filters automatically charge themselves as the air passes through. You can get this type of furnace filter made according to your preferences by spending more money. Electrostatic furnace filters are available in two models: disposable and permanent. A permanent electrostatic furnace filter will cost you more initially. Still, it can last for about eight to ten years if maintained properly. Whereas a disposable electrostatic furnace filter will only last for about one or two months.

High-Efficiency Pleated Furnace Filter

This furnace filter is one of the best furnace filters available in the market as it can filter even the smallest dust particles. This furnace filter uses synthetic cotton that is four or five inches thick. In most cases, you need to attach it to a metal grill. The purpose of this metal grill is to prevent leaks. Many medical facilities and hospitals use this filter to protect their patients from the harmful pollutants present in the air.

The Importance Of A Furnace Filter

Effective For Homes That Have Pets

Pets contribute massively to the impurities present in your homes; a high-quality furnace filter will prove effective against such pollutants by preventing them from entering the furnace system. Pets with a high degree of hair fall can clog up your air vents and ducting systems if you don’t use a potent furnace filter.

Allergy Relief

People that suffer from airborne allergies benefit from furnace filters as well. Do you suffer from an allergy and does it start acting up? That is a significant sign showing you either need to clean or change the filter present in your furnace. Many people use these filters also for improving the indoor air quality inside their homes. You should also use a furnace filter if your home has a high number of people living in it. The quality of air is seriously affected by the number of people living in a home.


What Is The Difference Between Air Filter And A Furnace Filter?

Essentially, a furnace filter is the same as an air filter. Both these filters’ main objective is to remove harmful particles from the air that enters your home through the central air system. If you have a typical central air system used for cooling and heating your home, your system most probably uses a standard filter for both purposes.

If your home has a separate heating and cooling system, then these systems will have two different filters that essentially have the same function. The only difference between a furnace filter and an air filter is that the first one heats the air before it continues through the system.

What happens if you don’t change your furnace filter?

If you don’t change your furnace filter, it’s like trying to breathe with a sock stuck in your mouth. The dirt and dust will clog up the filter and reduce the airflow. This can lead to reduced airflow and lower efficiency, which means your furnace will have to work harder to heat your home. Eventually, this can cause damage to your furnace and increase your energy bills.

Do all house furnaces have filters?

Not all houses have filters, but most newer ones do. If your furnace doesn’t have a filter, it’s a good idea to get one to keep your air clean and your furnace healthy.

How long does it take to change a furnace filter?

Changing a furnace filter is super easy and only takes a few minutes. Just find the filter, pop out the old one, and replace it with a new one. You should do this every few months, depending on how much you use your furnace.

How much do furnace filters cost?

The cost of furnace filters depends on the type and size you need. HEPA filters cost around $20. Make sure you check your furnace specs to find the right one at your department store.


Furnace filters are essential for maintaining the quality of air that enters your home. I have described the function and purpose of a furnace filter along with its working. You now also have an idea about what types of furnace filters are present in the market, along with their features.

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