5 Negative Side Effects of Dirty Air Filters

Changing your home's air filters is a simple, five-minute, cheap task. Unfortunately, many homeowners put off replacing their air filters for months (if they ever get around to it at all). Here's the real cost behind ignoring one of your home's most fundamental needs...

Your house is often the biggest financial investment you'll ever make. HVAC air filters work in partnership with your house's heating and cooling system to keep it running smoothly and efficiently. So why not protect and preserve the costly systems that heat and cool your home, and keep your family comfortable during unbearably hot summers and blistering cold winters? Changing your home's air filter is one of the simplest, yet most powerfully effective ways to do just that. It only takes a few minutes, and the positive impacts are far-reaching: to your heating and cooling system's performance, to your energy bills and to the air you breathe.

First, you need to understand what makes this simple task so vital to your home's tip-top performance and the unfortunate fallout if you ignore it.

Since few homeowners know the real damage lurking behind dirty, clogged air filters, we've put together the top 5 ways in which they can ruin your home, your wallet and even your health.

How to measure your air filter

Not all home air filters are the same. In this video, we show you how to measure your home air filter’s dimensions to find the right size replacement before installation.

How to change your air filter

Ready to replace your air filter? Filterbuy expert show you a step-by-step process to replacing your home's air filter.

1. Dirty Air Filters Increase Your Electricity Bill

Dirty air filters cause your AC system to use more electricity - Filterbuy

Your central air conditioning depends on the continual recirculation of air. When that airflow is impeded by a dirty or clogged air filter, it means your system has to struggle much harder to cool your house. The harder the system has to work to pull air throughout your home, the more energy it requires and the higher your energy bills will be. This inefficiency intensifies as the filter becomes increasingly clogged. Simply put, anytime your system is pushed to work harder, it's costing you dearly (PLUS, you're getting less air for the money).

2. Dirty Air Filters Can Cause Frozen Evaporator Coils, Mold, Mildew, and Bacteria Growth

Old air filters can cause mold and mildew growth – Filterbuy

If your air filter gets too congested during the summer cooling season, it may cause lack of airflow to the evaporator or cooling coils. This lack of adequate airflow causes condensation that is normally produced during the cooling process to freeze. Frost buildup on coils or fans makes it more difficult for your AC unit to remove heat from the air and cool your home. It may even result in the ultimate headache and financial disaster: your air conditioning unit's total break down.

For A/C and heat pump systems, a clogged air filter can also cause the evaporator coil to get caked with dirt, mold or bacteria. This constrains the critical heat exchange process, making your A/C or heat pump system unable to effectively control indoor climate or remove proper amounts of humidity. The evaporator coil becomes like a petri dish, providing the perfect place for microorganisms to multiply.

3. Dirty Air Filters Reduce Airflow, Increasing Strain on Your Blower Fan

Blower fans are designed to push air through the filter. If the filter becomes too clogged with dust, dander and debris, then the blower has to struggle harder to pass the air through the blocked filter. Just as in point number one, this additional strain raises energy usage, which results in a higher utility bill. With reduced airflow, there's also a chance you'll experience inconsistent room temperatures (hot and cold spots) throughout your home.

Ultimately the blower fan motor can burn out, resulting in overheating and system collapse (as we'll explain in point number five...wait for it!).

4. Dirty Air Filters Lower Air Quality in Your Home

Image of an old, dirty air filter - Filterbuy

If the air filter is dirty, you can bet that the air you breathe is dirty too. One of the purposes of an air filter is to filter out all microscopic particles like dust, pollen, pet dander, bacteria, plant and mold spores, and even smoke. A blocked filter continuously recirculates those particles back into the home, causing you and your family any number of health-related symptoms, including headaches, fatigue, cold-like symptoms that don't ever seem to go away and chronic allergies. If you own pets, the indoor air quality will be even more miserable with a clogged filter.

5. Furnace failure

All of this undue strain on your HVAC - explained in points one through four above - can cause this very complex, very expensive system to stop working altogether. Basically, an overtaxed air blower may give out entirely, causing the whole system to fail and costing you thousands of dollars for repair or replacement. Spending $7 on an air filter doesn't sound so bad now, does it?

Given the money you've already invested in your home, not to mention the priority you place on your health, failing to change your air filters regularly just doesn't make sense. It only takes a few minutes, doesn't cost a ton of money, and (with less sniffles, sneezing and congestion) your family and pets will thank you for it.

As a best practice, high quality air filters typically require replacement once every three months. If you have multiple indoor pets or many people living in your home, however, you may need to change the filter more frequently, such as once a month.