Do Vent Filters Work?

Last Updated on December 9, 2020 by Kimberly Crawford

Most homeowners’ nightmares are how to control dust and allergens since they can pass through the smallest opening. Because of the stubborn nature of dust, various technologies have come up to try and solve the problem. One of them is the invention of vent filters.

But before you run into purchasing one, you must ask yourself if indeed filters work. Are vent filters are capable of slowing down air passage?

Well, it can block even large particles, stop insects from crawling in and out of the vent. Although it’s not as effective as HVAC filters, it can also allow you to recover anything that drops in it.

Understanding more about vent filters and how they work, read along with this great article as it gives you a more in-depth insight into this technology.

how do vent filters work

What is a Vent Filter?

What is a Vent Filter?

A vent filter is a specially designed grating that is inside an air vent. Air vent on the other side is a soft piece consisting of fiber, foam, or fabric that can extend on an opening and fit well. How vent filters operate is different from that of HVAC since it needs more than one filter in your home.

HVAC filters are always outside in a home central air unit. Meaning all air in the home must pass through it before proceeding to other parts of the system. But vent filters offer the last step filtration that allows in air free of dust or bacteria. It only provides a single filtration. You’ll need several vent filters if your home needs more than one filtration system.

Remember, vent filters are less effective than HVAC and can interfere with the central air system that is trying to cool your house.  It would help if you also replaced your vent filters regularly.

Vent filters come in three various forms. The First one is the disposable activated carbon which does the filtration of dust, dirt, and fumes. The other one is washable electrostatic polypropylene, mainly for dust and dirt. The last type of vent filter is disposable non-woven, which is also for dust and dirt.

How Do Vent Filters Work?

air filter works

Vent filter’s main work is to prevent dirt and allergens from entering the air you breathe. The air in your house comes from the central air system. Vent filter purifies the air further after the air system has removed impurities, making it cleaner. The vent filters are part of the central air unit though they’re in the outer part.

Before air enters your home, they have to pass through vent filters meaning they’re responsible for the clean air you breathe in your home. It’s not easy seeing vent since there are at the back in a hidden layer after the filters.

Understanding how a vent filter works is never easy. But you should know that air passes through the different layers of foam or fiber. Then it goes through the central air system, where it forces its way into your home. The filtration takes place naturally until it reaches the vent filters where it meets the fabric that blocks the vent. During this period, impurities such as dust or dirt get to come out and remain on the fabric.

The filtration occurs at every vent with a filter, so the air that will be entering your home will be free of impurities and health hazards.

Do Air Vent Filters Restrict Airflow?

 Air vent filters have a way restricts airflow, which is one of the disadvantages of using it. The filters will reduce the airspeed as objects pile up on them. With time as the particles build-up increases, the air restriction also rises. When air restriction happens in the vent filter, the system will strain and consume much power. In the end, the air system will overheat, making it work slower.

If you intend to buy an air vent filter, ensure you pick one with a lower MERV (Minimum Efficiency Reporting Value). The rating should range between 6 and 8 so that less air restriction happens. A lower MERV rating means less air restriction in the vent filter, so your house will have sufficient airflow. But remember, it will allow more objects through if it doesn’t restrict the air.

Pros of Vent Filters

Like any other part of an HVAC system, vent filters have their good side, making it a better choice. We’ll look at its advantages to enable you to know the additional value it can bring to your home.

  • Vent filters protect your family against dust and dirt
  • Allows you and your family have a pure air supply
  • Vent filters are capable of catching small objects and stop the insect’s migration
  • It comes in various designs giving you options to pick from
  • If you have pets but allergic to their hair, consider using vent filters
  • Easy to maintain since you only need to replace the old one

Cons of Vent Filters

Vent filters also have their bad side, which you should look at before buying. The disadvantages are as follows;

  • It restricts airflow making the vent filter not work properly
  • It requires regular changing, which is costly
  • Vent filters can easily heat up when there are particles build-up

Do Vent Filters Work?

You could be wondering if vent filters work effectively.  But if you’ve been keen, you’ll realize we have the answer just before this. Don’t worry we’ll let you understand better if the vent filter works here.

First, you should understand that vent filters’ main work is to clean impurities in the air you breathe. It works with the central air system to give your home fresh cool air. It’s the last layer where air filtration occurs. The answer to the question above of whether vent filters work is yes. However, it doesn’t work effectively as other types of filters. Confusing right?

You must understand that the effectiveness of filters relates to the MERV rating. The higher the rating, the less effective though vent filter doesn’t have a MERV rating. But if you want more pure air, consider combining it with HVAC.

Do I Need Filters in My Return Vents?

Like any machine, HVAC needs to operate when it’s clean and with no dust. When you allow objects and debris to build up in it, it can result in overheating. So, it is wise to do regular maintenance to have the machine serve you longer. When it’s clean, you’ll also be getting clean and pure air.

Having a return filter will ensure your device cleans the air before it gets into the machinery. It’s important to have it as it will clean the dirt making your device serve you longer. You can maintain its cleanliness by replacing it with a new one.

How Often Should Vent Filters Be Changed?

replace air filters

When you want your vent filter to serve you for a long time, you should ensure it’s clean. The best and easy way to maintain its cleanliness is by changing it regularly. When you keep it clean, you won’t be paying high electricity bills since a dirty filter consumes much power. The major challenge most homeowners have is forgetting to change the filters to keep it clean.

But please change the air filter in your home after every 30 days. Thirty days is for the vent filter with cheap fiberglass. But if you have a high standard pleated filter, you can change them after six months. Remember, this recommendation is in line with filters of average use and not their size or type.

Keep in mind that the longer the filter serves you without getting a replacement, the higher its chances of spoiling.

How Many Return Vents Should A House Have?

Some years back, contractors could install one big return vent for the whole house. However, with time this has changed as homeowners have seen the importance of having sufficient airflow. Now you can install return vents per room and at times even have even more than one.

If you have several return vents in your house, you’ll have consistent air pressure. But if you prefer putting one return vent for the whole house, ensure you’ll be opening doors and windows too. Failure to open the doors or windows means your home won’t have adequate air circulation.


There are many debates on whether vent filters work or not. But one thing you should understand is that, like any machine, vent filters have their advantages and disadvantages. You should understand all these well before installing them in your home. Suppose you want pure air; you should fix vent filters.

Remember, they can trap insects and other objects, which are always a nightmare in most homes. If you want the machine to serve you longer, ensure you maintain its cleanliness by changing it regularly. Get to understand the different types of vent filters so that you don’t end up buying the wrong one. Don’t forget to look at its disadvantages since it’s something that can inconvenience you.

You should also ensure you have more return vents to have a constant and clean air supply. If you can afford to fix more than one vent filter per room, the better.