Did you know that clogged air filters are the primary cause of heating and cooling system problems?
Dust and debris in a home air filter restrict air flow, which forces your furnace to strain and use more energy to heat or cool your home. Just like replacing your car engine’s oil and air filter every 3,000 miles, a clean HVAC air filter protects your furnace system from becoming damaged and, ultimately, failing entirely.
But how can such a simple and relatively inexpensive component have such a big impact on energy consumption, equipment life and air quality? In other words, how can a $15-30 filter protect a $2,500-$3,500 heating and cooling system?
To answer this question, we first need to understand how your home is heated and cooled and then how air filter clogs prevent your system from operating efficiently.
How a Furnace Works
A forced-air system, which is the most common heating and cooling system, uses a heat exchange to heat or cool incoming air that is then blown through metal/flexible ducts to the various rooms in your home.
As the warmed or cooled air flows into the rooms, the unit’s fan pulls existing air out of the rooms via a separate set of “return” ducts and toward the heat exchange (where it is again heated or cooled). This circular cycle continues until the desired temperature is reached.
Here’s a good guide on how often you should change your air filter.
What Happens When Your Air Filter Is Clogged?
When your air filter is clogged, your air handler must work harder to compensate for the blockage of air flow.
In addition to driving up your utility bill, the reduced air flow through your heating and cooling system can cause your heat exchanger to overheat and shut off too quickly, preventing your house from warming up. If that happens too often, the electronic "limit switch" safeguard can fail, and then the furnace won't fire up at all. This service call and new part can easily cost you $175.
So what’s the big deal? Does an air filter really matter? In an effort to answer this, let’s take a look at what happens if you do not routinely change your heating and cooling filter. Here are some clogged furnace filter symptoms:
1. Clogs Generate Increased Energy Consumption:
Because the system relies on the constant recirculation of air, the performance of your heating and cooling system’s blower fan can have a big impact on your home’s energy consumption. The harder this fan has to work to draw air throughout your home, the higher your energy bills will be. In fact, a clogged filter can use 15% more energy, according to the Department of Energy. This inefficiency increases quickly as the filter becomes more and more clogged, or until the filter is serviced.
2. Clogs Cause Frozen Evaporator Coils:
If your air filter clogs during the summer cooling season, this can cause the evaporator or cooling coil to freeze up because not enough air is moving past the coil to dissipate the condensation that is normally produced during the cooling process.
Lack of adequate airflow causes this condensation to freeze – reducing the unit’s ability to remove heat from the air (e.g., cool your home) and, most likely, eventually causing your air conditioner to break down.
3. Clogs Lead to Inadequate Heating/Cooling:
Blower fans push the air through the filter. If the filter becomes too clogged with dust, dander and debris,then the blower has to strain harder to pass the air through a clogged filter. With reduced airflow you can experience hot and cold spots in your home, and it can be difficult to reach your desired indoor temperature levels.
With less air flowing through the system due to the clog, the central air conditioning and heating system will run longer in an effort to heat the home, raising energy usage. In fact, according to a study by the Florida Public Service Commission, the number two cause of high energy bills in the summer was a clogged air filter.
4. Clogs Contribute to Unhealthy Air:
A clogged air filter will allow all that dust and debris that should be filtered out to be re-circulated back into your home. This can cause chronic allergies and especially be dangerous for people with asthma or other respiratory conditions.
If you own pets or keep many chemicals around the house, the indoor air quality will be even worse with a clogged filter. You might not notice a sniffle here or there, but over time, poor indoor air quality will impact your health in a very negative way.
5. Clogs Lead to Furnace Failure:
Can a clogged air filter cause a heater to stop? The answer is yes, and likely the costliest result of an improperly changed air filter may be the internal damage it deals to your central air conditioning and heating system. According to the Diamond Certified Organization, a clogged furnace air filter is the primary cause of equipment failure. Essentially, that overworked air blower discussed above may give out entirely, causing the whole system to fail, an outcome that can cost thousands of dollars to repair!
Here’s a good guide to know how to change your home air filter.
Additional Resources About Unclogged Air Filters
Check out how valuable clean air filters are for your home:
- How much are clogged air filters costing you?
- How to improve Indoor Air Quality
- Tips About Your Furnace Filter from the American Lung Association from the Upper Midwest Health House (pdf)
- Air Filters Clear the Air
When you think how much can go wrong when you have clogged air filters, you take to heart the benefit that an air filter clog detector offers. Don't you think?