Is it Safe to Run Your AC Without a Filter? A Phoenix Tech Answers

The short answer: You can get away with running your AC without a filter for a short amount of time without hurting your system.

That being said, running your AC without a filter for longer than 6-8 hours can cause serious damage to your AC system and significantly lower the quality of the air in your home.

Below, let’s take a look at how your air filter works and the negative effects of running your AC system without a filter.

Your AC filter has one main job: to block dirt and debris from entering your AC system and therefore your home’s air.

Your AC sucks in air from your home, strips that air of heat and then blows that air back into your home. Your air filter is the barrier in front of your AC’s return vent (the vent that sucks air into your system). Its job is to prevent dirt and debris from getting sucked into your AC system along with air.

When you don’t have an AC filter in place, dirt and debris get pulled into the system. Some of that debris gets blown back into your home and some of it stays and accumulates in the HVAC system. Ultimately, this can greatly lower your home’s air quality and dust and debris can damage your home’s system, resulting in potentially costly repairs or replacements.

As we mentioned above, running your AC without an air filter can cause negative effects, including:

• Increased energy bills
• Damaged compressor
• Decreased air quality
• Frozen evaporator coils
• Less conditioned air
• More dust around your home

Let’s look at the two biggest issues in more detail...

When you run your AC without an air filter in place, your AC is sucking in “dirty” air and circulating that air back into your home. This causes two main issues for you:

1. Instead of breathing in air that has been filtered, you’re breathing air with debris in it
2. Your AC is blowing air + dust around your home, increasing the chance for dust and other debris to settle on furniture and other surfaces

When you run your AC system without a filter, the dust gets sucked into your indoor AC unit and settles on a part of that system called the evaporator coils.

When there is dust on the evaporator coils, they can’t absorb as much heat from your home as they need to, causing the coils to freeze.

If your evaporator coils are frozen, it means that you’ll run into issues like:

• Increased energy bills- When your evaporator coils are frozen, they can’t absorb as much heat from your home, so your AC has to run for longer periods of time to cool your house. This will lead to increased energy bills over time.
• Damaged compressor- If your evaporator coils are frozen and you keep running your system, it could damage your AC compressor. Your AC compressor is located in your outdoor unit and is often referred to as the “heart” of your system. The compressor is responsible for “pumping” refrigerant through your AC system. Because your AC wouldn’t work without the compressor, replacing this part of your system is very expensive and can cost up to $3,500.
• Less conditioned air- If your evaporator coils are frozen, your AC system will probably be producing less conditioned air. If you put your hand over your AC vent and notice that there is very little air coming out, but the air itself is cooler than normal, you may have a frozen or plugged AC evaporator coil.