Signs of a Dirty Furnace Filter
If your furnace is having issues, it's time to check your furnace filter and ensure it isn't dirty. Changing your filter regularly can prevent your HVAC system from failing altogether.
Learn the factors that cause dirty furnace filters, dirty air filter symptoms to look out for, and what to do about them
While the average lifespan of an HVAC system is approximately 20 years, one dirty furnace filter can cut that time in half – or worse. It is crucial to regularly replace your air filters to avoid a catastrophically expensive, potentially dangerous situation.
Whether your home has a furnace or an air conditioner, the air in it runs through an HVAC air filter. The filter is meant to capture particles like dust, pollen, pet dander, and – depending on the efficiency of the filter – even bacteria and viruses. A clogged air filter can create big problems, so you'll want to recognize the signs and know what to do about it.
What Are the Most Common Signs That My Furnace Filter Is Dirty?
Here are some signs that indicate your furnace filter is dirty and needs replacement include:
Reduced Airflow: If your filter is blocked, it might be preventing air from passing through the system if your vents are producing less air.
Higher Energy Bills: A dirty filter forces your furnace to work harder if your filter is dirty, leading to higher utility expenses.
Uneven Heating: Because of limited airflow, heat can’t be distributed evenly in your home and you may find that some rooms are colder than others.
Increased Dust in Your Home: A clogged filter can let dust and debris pass through, increasing the amount of dust that settles on surfaces in your home.
Strange Noises from the Furnace: When the furnace is overworked, it might generate odd noises like banging or whistling when it tries to function properly.
Frequent Cycling: When the filter is dirty, the furnace struggles to maintain the proper temperature and turns on and off more frequently.
Visible Dirt or Dust on the Filter: It's time to clean or replace it if you examine it and it's blocked with dust and dirt.
Dirty furnace filter symptoms can be avoided by routinely inspecting and replacing your filter, which will keep your system operating effectively.
How Does a Dirty Furnace Filter Affect My Heating System?
A dirty furnace filter restricts airflow and can lead to expensive problems. It results in uneven heating making some parts of your home colder than others. With clogged dirty furnace filters, your furnace has to work harder to circulate the air, which makes your utility bill rise. This can make the blower motor overheat or fail, negatively impacting your system. You might wonder if a dirty furnace filter increases filtration. It doesn’t.
In fact, it does the opposite. When a filter is dirty, the dirt restricts airflow through the furnace. This can cause a breakdown if enough of it accumulates. Sometimes it allows the dirt and particles to bypass the filter, and your furnace then will struggle to operate properly. Rather than improving filtration, clogged air filters can damage your whole system. This is why you need to change your filter regularly. Replacing or cleaning your filter ensures even heating so your system will keep working efficiently.
Dirty Air Filter Symptoms
Stay vigilant in keeping an eye out for dirty air filter symptoms so you don’t end up with a clogged AC filter becoming a burden on your HVAC system.
- More dust has been piling up in your home.
- Your air filter appears gray in color and seems to be covered in pollutants.
- You see unusual increases in your energy bill.
- The cycles in your HVAC system have increased in length.
Pollutants that Cause Dirty HVAC Filters
Most homes in the US have a central air conditioning unit that cools the house. In these kinds of systems, air circulates from room to room through ductwork. On its way to the unit, air passes through a filter that removes large particles that could settle on and damage the unit if they don't get trapped. The question on most people's mind is – Why does your air filter get so dirty?
- Dust, dirt, and fibers – Dead skin cells, dirt tracked in from outside, and fibers from upholstered furniture, carpet, and bedding all contribute to household dust. As these pollutants are whipped up, they enter the ductwork and clog up the furnace filter.
- Smoking indoors – Cigarette smoke wafts through the air when you smoke indoors, making its way to the filter and clogging it up faster than if you choose to smoke outside.
- Pet dander – Dogs and cats shed, which gets hair everywhere. Much of this hair is swept up into the ductwork, where the furnace filter catches it so it can't re-circulate back into your home.
- Pollen – Even though flowers grow outside, it's possible for pollen to hitch a ride on pets, clothing, shoes, hair, and skin. Furnace filters made specifically for allergy season are the most effective at trapping pollen particles for cleaner indoor air.
- Mold spores – Efficient furnace filters for the home trap mold spores as they travel through the ductwork. If excess humidity dampens the filter, mold could start to grow here if you don't change the filter frequently enough.
Why Do My Energy Bills Suddenly Increase When the Filter Is Dirty?
Your energy bills increase when your furnace filter is dirty because it works harder to circulate the air in your house. To make up for the restricted airflow, the blower motor also has to operate longer and at a higher output, and this increases the amount of energy the system uses and also expenses. Dirty air filters can cause uneven heating, and create wear and tear which can result in costly repair bills. Regularly changing your furnace filter can prevent problems from occurring and keep your utility bills under control.
How Does Poor Indoor Air Quality Indicate a Dirty Furnace Filter?
A dirty furnace filter lets dust, debris, and allergens spread throughout your house, and contributes to poor indoor air quality. Pollutants get past your filter and into your ventilation system when your filter is blocked because it can’t absorb airborne particles. Dust accumulates on surfaces and respiratory irritants in the air may develop. Unclean filters can cause moisture to build up which can deteriorate your air quality by causing mold growth and germs. If you experience asthma or allergy symptoms or if you detect dust or a musty odor, your furnace filter may need to be replaced.
When Should I Replace My Furnace Filter to Avoid Damage?
You should replace your furnace filter every 1 to 3 months to ensure your furnace doesn't get damaged. If you have a pet or are a smoker, replace your filter every 30 days because it can clog faster. Inspect your furnace filter on a regular basis to ensure your furnace continues operating properly.
Can a Dirty Furnace Filter Cause Unusual Furnace Odors?
When a furnace filter gets dirty, it traps particles that can cause musty or burning smells. Moisture can get trapped causing mildew or mold or the system can overheat causing a weird smell. Recirculating pet hair or smoke can create unpleasant odors too. These reasons are just part of why it's important to change your dirty furnace air filter.
How Do Pets Affect the Frequency of Furnace Filter Replacement?
Due to the pet hair, dander, and dust they can cause, you should change your furnace filter more frequently if you have pets. Particles from these can clog your filter rapidly, reducing airflow and possibly causing health issues. The kind of pets you have, and how much shedding they do, may affect how often you should check and change your filter.
What Is the Connection Between Filter Neglect and Frequent Cycling?
If you don’t replace your furnace filter, it can cause your system to cycle on and off repeatedly, which is called short cycling. Your system might overheat and prematurely shut off, then restart again, while attempting to maintain the temperature. This can waste energy and increase your utility bill, or cause a breakdown. Replace your filter when it's dirty to prevent your system from short cycling.
Does a Dirty Filter Influence the Cleanliness of My Duct System?
Dust, debris, and pet hair can bypass your filter and build up in your ductwork. These can reduce the effectiveness of your HVAC system, bringing contamination into your home. If your ducts get dirty or have bacteria or mold in them, you’ll need professional duct cleaning to ensure you have healthy air quality.
Are There Any Warning Sounds That Suggest a Dirty Furnace Filter?
A whistling noise could happen when air is pulled through a filter that is clogged up, due to increased air pressure. Or the motor could get louder when this happens. Rattling noises may occur if the system is working harder due to debris. Check your air filter if you hear odd sounds and replace it if it's dirty. Otherwise, these might indicate system damage.
Other Factors That May Create a Clogged AC Filter and Cause Dirty Air Filter Symptoms
- Cold weather – When the temperature drops, your furnace works harder to keep your home warm. This sends more air flowing through the filter and increases the amount of particles that become trapped there, dirtying your filter faster than normal. Summertime heat can cause similar problems for air conditioners. Both systems utilize air filters so it’s important to keep an eye out for dirty air filter symptoms year round.
- Thermostat set to on – This setting means the furnace blower or air conditioner runs all the time. Auto is a better setting for energy efficiency and helps your filter last longer as well.
- A home full of contaminants – More pets, people, and dust in your home cause more contaminants to fly through the air. If you have multiple pets and people living at home, you should expect your furnace filter to become dirty faster.
- Infrequent air filter replacement – The general guideline is to check your filter once a month and change it if it looks clogged. No filter should be installed for longer than three months. Try to change your filter with the changing seasons to keep up with this recommendation or follow our guide on how often to replace your furnace filter.
What Does a Dirty Furnace Filter Look Like?
A dirty air filter is gross – often coated in gray or tan filth that may flake or fall off when disturbed. If it looks like this, it's time to replace your filter.
Potential Problems Caused by a Dirty Furnace Filter
Simply ignoring or accepting a clogged air filter is never a good idea. Not only can the dust cause health issues due to increased dust and allergens in the air, but your HVAC system and furnace filter can malfunction, decreasing the flow of heat or air in your home or freezing condensation on the cooling coils (also preventing proper airflow). Dirty air filter symptoms can lead to serious problems:
- Recycling of air filled with pollen, dust, mold, and other allergens trapped in the filter.
- Rise in allergic reactions like clogged sinuses, headaches, itchy eyes and throat, and more.
- Inflation of energy bills due to an upsurge of up to 15% energy usage.
- Growth of bacteria, as a result of frozen coils.
- Ultimate destruction HVAC system, potentially costing you thousands of dollars.
Now that you know what causes your air filter to become dirty, it's time to stock up on replacements. Remember, choosing high-efficiency air filters for extreme seasons can be of great help in keeping the air in your home clean.
Conclusion
Don’t ignore it when your furnace filter needs to be replaced. It could cost you thousands of dollars if it causes problems with your HVAC system. Contact Air Filters Delivered for all types of filter replacements. We have what you need.
For more useful information about caring for your HVAC unit – like how to safely dispose of a dirty air filter, check out our Helpful Tips page.
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