Furnace filters are often looked at and considered a bit of an annoyance when it comes to keeping your home properly heated. They take a lot of attention compared to the needs of the rest of your HVAC system. Because filters require maintenance, it’s easy to question whether it’s possible to run your furnace without a filter and if there are consequences for doing so.

Why Are Furnace Filters Important?

Furnace filters are crucial to the life of your furnace. Before digging into the problems caused by running your unit without a filter, let’s explore why they’re important in the first place.

Air is primarily composed of nitrogen and oxygen, along with minor parts of other gases like carbon dioxide. Beyond the gases, the air also has water vapor and a variety of contaminants, including dust, biological particles, chemicals, and more.

The amount of these extra particles defines your air quality, with more particles leading to lower air quality. Your furnace filter helps keep these contaminants out of your furnace, where they’ll wreak havoc on your system’s efficiency and service life.

No Filter Could Damage Your Furnace

One of the first things you need to be concerned with is airborne contaminants causing damage to your furnace. These contaminants cause damage in a couple of ways.

First, the airborne contaminants collect inside your system, typically on the heat exchanger and the circulating fan wheel. Deeper in the system, the contaminants will collect in the ducts on the way to the vents. These contaminants create airflow restrictions, which causes the heat to build up in the unit, accelerating wear on system components.

The second risk is the physical damage dust and dirt causes to system components. Many components within the furnace are susceptible to physical damage, including electrical components, your circulating fan motor, and the heat exchanger. The more contaminants that enter your system, the more damage they’ll likely cause and the more quickly the system damage will occur.

No Filter Causes Poor Air Quality

Air quality is a growing issue, with the number of chemicals in our homes constantly increasing. When your furnace doesn’t have an air filter, the contaminants in the air continue circulating and collecting. As the air cycles through your HVAC system, there will be more contaminants that are picked back up and carried back into your home.

The problem with poor air quality goes beyond what it does to your HVAC system. It also poses health risks for your family, including respiratory irritation and distress. Poor air quality has been linked to chronic problems like asthma and COPD.

Additionally, poor air quality means there are more contaminants that’ll eventually fall out of the air and land in your home. This leads to more dusting and vacuuming to keep your home clean.

No Filter Poses a Fire Hazard

A very common fear is having a house fire, and neglecting proper furnace maintenance increases that risk. This is especially true if you try to run your furnace without a filter.

All those particles that collect inside may not seem like a big deal until they collect and have heat applied. A little dust layer that accumulates on a heat exchanger will cause a little odor. However, when you have significant layers, it can cause combustion, especially if there’s an electrical short or arcing.

If dust inside your furnace ignites, it’s going to cause irreparable damage to the furnace, at a minimum. In extreme cases, it could ignite a house fire, all because of built-up contaminants in your furnace.

No Filter Makes You Prone to Illness

Not only does poor air quality cause problems with asthma and COPD, but it also leads to immune system problems. Your immune system sees dust and pet dander as contagions and reacts to them like any other foreign invader.

When your immune system is constantly strained due to the air quality, you’re more susceptible to various illnesses and viruses. You spend more time inside over the winter, usually around other people, which continually exposes you to these contagions. You can easily reduce your susceptibility by keeping your air filter in place and relatively clean.

What Happens With a Dirty Filter?

Dirty air filters are just as bad, if not actually worse in the short term, than running your furnace without a filter at all. Filters will collect many of the contaminants floating around in the air, reducing many of the risks associated with not having a filter.

However, they will eventually clog over time, restricting the amount of air flowing through your system. Therefore, you need to change your filter regularly.

Forgetting to change your filter will cause many of the same problems as operating your furnace without one. The difference is that you’ll likely experience these much sooner than if the problem was deeper in your system. While this may make you question why to use a filter, this is good because it’s an easy fix by simply changing the filter.

How Often Should You Change Filters?

Generally, the common recommendation for changing your furnace filter is about every 90 days. However, there are really a variety of factors that may increase or decrease that frequency.

First, look at the kind of filter you have. Most 1-inch and 2-inch filters need replacing about every 90 days. If your furnace uses 3- or 4-inch filters, that extends its life up to between six and nine months. Larger 5- or 6-inch filters should last between nine and twelve months.

Don’t try to use a larger filter unless your furnace was specifically designed to work with them. Doing so may reduce airflow through your system, leading to some of these same problems the filter should prevent.

The change interval is also greatly dependent on having generally good air quality. If you have poor air quality because of many pets, smoking in your house, or not cleaning regularly, you may need to change them more often. If you’ve done a household project that produces a lot of dust recently, plan to change them shortly after the project wraps up.

Extending Your Filter’s Life

To make sure you get your filter changed before it causes unnecessary strain on your furnace, plan to check it every month. This is especially true if you don’t know the quality of your air.

When you do check your filter, plan to gently vacuum the intake side to remove any loose dust and debris. It’s important to only vacuum the intake side as you can damage the filter by trying to draw the contaminants through it.

Most furnaces use paper or fiberglass filters. Avoid using water or solvents to try to clean these. Doing so will damage the filter and either create an airflow restriction or increase the pore size, allowing more contaminants through.

People in Harrisburg and the surrounding areas have depended on HB Home Service Team to keep them comfortable throughout the winter for more than a century. Our expert technicians provide heating and cooling installation, maintenance, and repair, plus a full range of plumbing services. Call to schedule your furnace maintenance or repair with one of our trusted technicians today.

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