Are HVAC Filters Necessary? A Comprehensive Guide

Commercial and residential cooling and heating systems need a filter to remove impurities before they suck indoor air into the system and exhaust it back to areas that are supposed to heat or cool. An HVAC system can work without a filter, but this is not recommended. At its most basic function, an air filter removes impurities such as dust, pet dander, or even bacteria from the air that flows through the system. Not only does this improve the air quality inside your home, but it also protects your HVAC system from potential damage. The primary purpose of a filter is to protect HVAC equipment, not improve indoor air quality, as many homeowners have been led to believe.

Many oven manufacturers recommend using an inexpensive fiberglass filter, but when I asked a representative of one of the major manufacturers, his answer was “no comment”. Supply grilles don't need, in fact, they shouldn't have an air filter. Why? The filter belongs to the return side of the heating and air conditioning system of your HVAC. It is “essential to have one there”. And if you have a correct size return air filter that is properly installed, then there is no need for a supply vent filter.

In fact, it will cause more problems than you could already have. Because some homeowners have things like dust and musty odors caused by mold spores coming out of supply grilles and want to prevent them from getting into the air they breathe. If that's the case in your home, our ducts need cleaning and sealing. That's the answer to the problem, don't mask the problem or make it worse with a vent filter on all supply grilles. The way to prevent pollutants that cause allergies from leaving your home is to have the correct air filter on the return side and have the duct work properly sealed to prevent dust and other unpleasant things from sucking dust and other unpleasant things out of your attic or basement and coming out of the supply grilles. The first time we received this question, we asked ourselves: “Why would you do that? But one of our professionals pointed out that many people are concerned that allergens will float around the house and cause allergy outbreaks, asthma attacks and, in general, poor indoor air quality (CAI).While not related to the issue of a supply-side vent filter, isolating the ducts is a great idea with an immediate return on investment.

There is evidence that duct network sealing and insulation will pay for itself with lower bills only in a few years. And then you save money every month and you also use less energy. We say this because an HVAC technician is better trained and has more knowledge about ducts and their proper cleaning. They will have the right solution. How much does duct cleaning cost? This Air Conditioning Duct Cleaning Cost Has the Answer.

The primary function of an oven filter is to trap airborne contaminants, not for air quality reasons, but to keep them out of the heating and cooling system. However, because the filter removes contaminants for the benefit of the system, air quality also benefits from its removal. In general, it is recommended to have an air filter on each return grille (as long as you choose the one of the correct size and thickness).


will improve the air quality in your home and protect HVAC equipment from dust, pollen, pet dander and hair. Some HVAC systems aren't strong enough to push air through more restrictive filters that block smaller particles, that is, those with a higher MERV or CADR rating, which can reduce airflow and cause your home to heat and cool less efficiently. If there is one there, as there should be, adding a vent filter to each vent will cause several problems.

Air filters trap pet hair, dust, and other irritating particles so that the air conditioning system returns fresh, clean air to your home. Proper maintenance of air filters, whether replacing or washing them regularly, is crucial not only to providing clean air in your home but also to maintaining the proper functioning of your HVAC system. Even though there are filters that come with a rating as high as 20, they could restrict airflow. If your home has too many air pollutants circulating through it, special indoor air quality devices can help, and the first step is usually to install special air filters. Some brands have created their own rating systems such as Home Depot Filter Performance Rating and 3M Microparticle Performance Rating. Compared to other DIY home improvement projects changing air filters is a quick and painless process that can be done in less than an hour.

When air enters the system it passes through a filter that captures a large amount of particles in the air. Filters that are too thick or too thin can restrict airflow which in turn will cause the system to overwork. While these factors affect the frequency of air filter replacement you should visually inspect the filter every month for excessive particulate buildup. Thicker filters have more media available to capture contaminants so a 5-inch filter requires less frequent changes than a 1-inch filter. Or thanks to today's smart home technology you can even purchase smart filters such as 3M Filtrete smart air filters that use sensors to monitor airflow. But what about the things that are already there? Putting those air vent filters cut off and tight won't help.

Shana Gojcaj
Shana Gojcaj

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