Although an air filter replacement is not a priority for most people, it should be. Why? Well, many potential problems and expensive repair bills can be avoided, or the risks mitigated with a simple air filter change. This is easy to do, the full instructions are detailed in the owner’s manual, and a fresh filter is an inexpensive component. But, many people forget to change their filters, and this is the least expensive form of preventative maintenance that anyone can do. In this article, we will show you how a clogged air filter can damage your furnace.

A Brief Air Filter Primer

If you have a forced-air HVAC system that pushes treated air (warm or cool) through the home to air vents, you need a clean and clear air filter. Most HVAC systems have multiple air filters, and one of them will be located in the furnace. The system pulls fresh air into the home, and this is distributed and recycled through the air filter multiple times per day. But, when the air is moving through the home, it can pick up a number of airborne contaminants, including dirt, dust, pet hair, pollen, dust mites, and more. These contaminants lower the indoor air quality (IAQ), and they ultimately end up in the air filter. As you can imagine, the air filter will become clogged with these contaminants, and it must be replaced regularly.

What is the Purpose of the Air Filter?

Many people believe that the primary purpose of an air filter is to improve the IAQ. This is only partially correct, the air quality will be improved, but the air filter has a more important job. There are sensitive components in the HVAC system that degrade in performance and energy efficiency when they become dirty. Dirty components are more prone to failure and an earlier than expected replacement. Over time this can increase the cost of ownership dramatically, and this is why regular air filter changes are essential.

5 Clogged Air Filter Problems Explained

There are five main problems caused by clogged air filters:

1.   A Loss of Energy Efficiency

When an air filter becomes clogged, the blower unit will need to work harder to push the air through the obstruction. This requires more energy to achieve, and the EPA estimates that an average home consumes 15% more energy if the filter is dirty. If you want to lower your monthly energy bill, it’s a good idea to check and change the air filter regularly.

2.   Degraded IAQ

Although cleaner air is a secondary function of an air filter, it is true that the IAQ will decline if the filter is clogged. The airborne particulates will continue to circulate in the air, and you may notice that your home is dustier than usual. This is especially true if you have pets in your home because pet hair clogs a filter faster than normal. The first people that notice these problems are those with allergies and pre-existing respiratory illnesses. They may have trouble breathing easily because the air is laced with contaminants.

3.   Degraded Heating Performance

Any forced-air system cannot operate effectively if there is a lack of air flow. A clogged filter diminishes the air flow considerably, and if you hold your hand up to the vent, you can feel the difference. The furnace is not designed to dissipate easily, and a clogged filter will cause overheating issues. Modern furnaces have a built-in limit switch; this safety feature is designed to kick in if the temperature rises too high. This process is automatic, and it can take some time for the furnace to cool sufficiently to begin working again. But, if the core issue is not dealt with, this will happen again, and the dirty air filter must be replaced to rectify the problem.

4.   Furnace Damage

A clogged air filter will lower the airflow, which causes the aforementioned overheating problems and overworking as the system attempts to compensate. This can damage the pilot light, pressure switches, gas valves, the fan, and the heat exchanger. These components can be expensive to replace, but a damaged heat exchanger is a more serious problem. A cracked heat exchanger can release carbon monoxide into the home, which is a deadly toxic gas that is not safe in any volume. Carbon monoxide is colorless, and odorless, and it has the potential to be lethal even in small concentrations.

5.   Housefires

In extreme scenarios, a dirty furnace filter could cause a house fire. The limit switches can malfunction, and the risks rise with an inefficient furnace. The buildup of heat could cause a fire and even an explosion if the dirty filter is sucked into an overworked furnace.

How Often Should I Change the Furnace Filter?

An air filter in the furnace should be changed at least once every six months. But, if you have kids or pets living in the home with you, it’s a good idea to change the filter more often. Children and animals tend to generate more airborne contaminants that can clog the filter faster. It’s also advisable to clean the filter housing too and the area around the furnace to prevent dust and dirt from entering the ducts and furnace. Declutter the area around the furnace to keep it cleaner, safer, and more efficient. The full instructions for filter changes and the filters you need are detailed in the owner’s manual for your furnace. If you’ve misplaced your manual, check online for a free pdf copy.

The Furnace is Not Working; What Should I Do?

The aforementioned problems may be avoided with regular filter changes. This is preferable to repairing or replacing failed furnace components which is expensive. If the furnace damage is extensive, it may be necessary to replace it entirely. If you have a furnace problem, it’s important to contact your local HVAC specialist to take a look at it for you.

If you need to schedule some essential maintenance for your furnace, contact your local heating and cooling specialist today.