Can I Run My AC Without a Filter? A Florida Tech Explains.

We get it—emergencies happen. One night you might take out and toss a dirty air filter only to realize that you don’t have a replacement filter and the shops are closed.

So, is it really that bad to run an AC without a filter? The short answer: You can get away with running your AC without a filter for a short period of time. However, doing so for longer than 6-8 hours can hurt your system and decrease your home’s indoor air quality.

To help explain our answer, we’ll examine the below questions in this article:

• What even is the purpose of an air filter?
• What are some problems that occur when you run an AC without a filter?

Have you been running your AC without a filter and want to check that no damage has been caused? No problem. Our team of technicians would be happy to inspect your AC system and provide air filter recommendations.

Think of your air filter like a bouncer. As warm air passes through the filter, large particles like dust, pollen, mold spores, etc., get trapped in its tightly woven material. Only clean air is allowed in. Your AC system then cools and blows that clean air back into your home.

The filter trapping contaminants helps it to:

• Purify your home’s air
• Keep your AC system free of dust and dirt

Without a filter, dirt and debris get sucked into your AC system and blown back into your home, staying and accumulating in your HVAC ductwork. Both scenarios can lower your air quality and potentially damage your HVAC system, resulting in costly repairs or replacements. The longer you run your AC without a filter, the more likely you are to need repairs.

Below, we'll discuss some problems that can occur when you run your AC without a filter for too long, including:

• Decreased air quality
• Frozen evaporator coils
• Increased energy bills
• Damaged compressor
• Less conditioned air

Without a filter to keep pollutants from circulating throughout your home, the indoor air quality will decrease. This is especially troublesome when you’re bringing in pollutants at the same time. Everything from pets to guests to leaky air ducts to vacuuming can increase the pollutants in your home.

With your AC blowing particles around your home, you might breathe in dust and other debris, and the particles can settle on your furniture and other household surfaces. These two situations can combine, causing:

• Flu-like symptoms
• Nose and throat irritation
• Respiratory condition aggravation
• Itchy, watery eyes
• Restless sleeping nights

As said above, running the AC without a filter allows dust and dirt to settle inside your AC system, which forces the system to cool your home ineffectively.

You see, evaporator coils are located in your inside AC unit and are filled with a cold chemical agent called refrigerant. As warm air passes over the cold coils, the refrigerant cools the air, and then the air is pushed throughout the home. However, when a thick layer of dirt covers the evaporator coils, the airflow over the coils is restricted and not enough warmth is absorbed.

Eventually, the already cold coils become frozen because there’s not enough heat counterbalancing the refrigerant. As we will describe in the following sections, frozen coils can lead to many problems.

Learn more in our article, “Why Is My Air Conditioner Frozen On the Inside?”

When the evaporator coils are frozen, they can’t absorb as much heat. Therefore, your AC must run for more extended periods to cool your home to your desired temperature. The increased energy consumption can lead to higher-than-normal monthly energy bills.

If you keep running your system without a filter, your evaporator coils might stay frozen, possibly damaging your AC’s compressor. The compressor is the system’s “heart” because it pumps refrigerant throughout its “veins.” Since your AC cannot work without a compressor, the cost of replacing it can be prohibitive and cost you around $2,500 or more.

Learn more in our article, “The Cost to Replace a Home’s AC Compressor in Florida.”

With frozen evaporator coils, your AC system is prone to producing less conditioned air. If you put your hand over your AC vent, you might feel either frigid air coming out in sparse amounts or warm air.

Need help replacing a clogged filter or want to check if your AC has any damage from running without a filter? Or do you want to upgrade your air filter to capture more air pollutants?

We can help. Just contact us, and we’ll send over one of our 5-star technicians to offer professional help and advice.