Is It Okay to Use Your HVAC System Without a Filter? (2023)

Every residential andcommercial HVACsystem uses a filter to remove impurities that are present in the air so it doesn’t blow them back into the indoor spaces and contribute to indoor air pollution. The filter also prevents particles from damaging the system.

Is It Okay to Use Your HVAC System Without a Filter? (1)

Is It Possible to Run an HVAC Unit Without a Filter?

The short answer is yes, your HVAC system can run without a filter. However, just because it can doesn’t mean it should. Running your HVAC unit without a filter is probably fine for a short period of time, but continuing to do so for over six hours is already pushing it. Unless you want your system to blow dirty air into your home or office and also risk damaging the unit, running the system without a filter is unwise.

How a Filter Works in an Air Conditioner.

Anair conditioningsystem has a filter to prevent dirt and debris from entering the unit and being blown into your indoor environment. The air conditioner sucks in air from your interior environment and removes the heat from it before releasing it back into the room. The return vent that sucks in air has a filter, which is the only thing standing between the clean air that enters the unit and the dirt and debris that was present in the air before it was sucked in.

Without a filter, there’s nothing to stop dust, pet dander and other debris from entering your home. Not all of that debris will get blown back into the air in the building. Some of it will get stuck and accumulate in the system.

(Video) Never use the furnace or AC system without a filter in place

When you allow cooling andheating systemsto run without a filter, there are negative effects:

Higher energy use.If you notice a spike in your electric bills, check the HVAC filter before calling a professional. If it’s dirty, try cleaning it. It might be what’s causing the unit to use more energy than it’s supposed to.

A dirty filter forces the HVAC unit to work harder than normal because it becomes more difficult for it to suck in air. A unit that works too hard uses more energy and is more likely to break down prematurely.

Now imagine using an HVAC system without a filter. All the dirt and debris that is sure to accumulate in the unit will make it even harder for it to work, so it will need more energy to reach the temperature you set on the thermostat.

It’s also possible that the unit is already damaged, which is why it’s burning up more energy than it used to.

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Damaged Compressor

Residential andcommercial HVACunits need regular maintenance and cleaning to prevent damage and premature failure. Without proper cleaning and inspections, mineral scales, grime and dust will continue to build up on the condenser coil over time. A clean condenser is necessary in order for the air conditioner to remove the heat that builds up in the system. The unit will continue to run in an attempt to cool your indoor environment, but it’s only a matter of time before the equipment fails.

Compressors fail all the time due to overheating. If there’s no filter to prevent particles from finding their way to the compressor coil, dirt buildup will occur much faster, which means your unit is likely to fail much sooner.

Poor Indoor Air Quality

The filter is responsible for removing impurities from the air before the HVAC system blows heated or cooled air back into the building. Without a filter, dust, pet dander and other particles are free to fly around your heated or cooled space.

There are filters designed to remove the tiniest particles, even bacteria and viruses. HEPA filters are known to capture air impurities with extraordinary efficiency. Particles measuring 0.01 micron or 10 nanometers and above can be captured by a true HEPA filter. The coronavirus responsible for the COVID-19 pandemic has particles with spikes that measure between 9 and 12 nanometers, which means an HVAC system or air purifier equipped with a HEPA filter can effectively reduce the presence of the coronavirus in the air.

Anair conditioningsystem that runs without a filter will have a huge negative impact on the quality of indoor air, possibly even leading to the spread of disease or an increase in allergic reactions. These can include eye and skin irritations, as well as flare-ups of respiratory diseases such as asthma.

(Video) How Many Air Filters Do You Need In Your HVAC System?

Research has shown that many homes and commercial spaces have air that’s more polluted than the air in the outdoor environment. As most people spend up to 90% of their time indoors, this is a concerning trend. While HVAC systems equipped with clean, efficient filters aren’t the only answer to this problem, it’s important that HVAC filters at least don’t contribute to it.

Less Efficient Heating & Cooling

As your HVAC system depends on a filter to remove impurities before indoor air is sucked into the system and then blown back out into the room, it needs the filtration system to be clean and efficient so the heated or cooled air can make your commercial space or home comfortable. A dirty filter compromises this capability. An absent air filter makes the system’s job even more difficult, and can soon lead to damage. If your system gives out on a searing hot summer day or a freezing winter night, you’ll have an extremely uncomfortable indoor experience.

Evaporator Coils Will Freeze

Evaporator coils contain a substance called refrigerant, which absorbs heat from your indoor air so your air conditioning system can blow cool air back into your home or office. They need to absorb this heat to continue functioning efficiently.

Without a filter, dust and other particles will combine with grime to cover the evaporator coils. As the coils will not be able to absorb as much heat as they used to, they’ll begin to freeze.

Frozen evaporator coils prevent your air conditioning unit from blowing back conditioned air, which is why your home or office may still feel hot even if you crank the thermostat to the lowest possible setting.

(Video) Why Are Air Filters Important for HVAC Systems?

The compressor, which pumps refrigerant through the system, can get damaged. This is an expensive part of your system, and you won’t have any choice but to replace it if it breaks.

Even if your air conditioner continues to run for a while with frozen evaporator coils, you’ll be paying more for the energy the system uses without the benefit of a clean, healthy AC.

Key Takeaway

Commercial and residential cooling andheating systemsneed a filter to remove impurities before they suck indoor air into the system and blow it back into the areas they’re supposed to heat or cool.

An HVAC system can run without a filter, but this is inadvisable. Without a filter, the system will draw in debris-laden air and return the same dirty air into your indoor environment, contributing to health problems. Before long, the system will be inundated with dirt and debris, which can cause it to malfunction and use up more energy, which will shorten its life.

We can tell you more about air filters and how to properly care for your HVAC system. Get in touch with Acker Heating & Cooling for your residential and commercial HVAC needs. Call us today at (706) 715-2607 or leave us a messagehere.

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What happens if I run my HVAC without a filter? ›

Without a filter, the condensation drain will fail to drain the moisture from your AC unit. This will result in condensation accumulation on the Freon tubing. The condensation will then start dripping down the pan, causing water damage to the whole system.

Can I run my HVAC without a filter for a day? ›

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.

Is no air filter better than a dirty one? ›

Running your air conditioner without a filter is worse than running it with a dirty one. Instead, get to the store as soon as possible for a replacement or call an HVAC professional for replacement. Without a filter, your air conditioner is at risk for severe and expensive problems.

Does it hurt to run furnace without filter? ›

If you choose to run a furnace without a filter, you leave your heating system susceptible to dirt and debris that will inevitably lead to expensive repairs and premature death of your HVAC system.

Is it OK to run without air filter? ›

Without an air filter in place, the engine may also be sucking dirt and debris in at the same time. This can cause damage to internal engine parts, such as valves, pistons and cylinder walls. The result is excessive oil consumption, poor engine performance, and eventually engine failure.

How long can I run my furnace without a filter? ›

Running your furnace without an air filter for a short period of time, like for a few hours or for a day, will not cause much damage. If you operate your heating and cooling system without an air filter for long periods of time, then the furnace could be damaged or run very poorly.

What if air filter is removed? ›

Without the air filter, all that stuff would get into the combustion chamber of your engine. That can cause a number of problems, such as a drop in power, decreased fuel efficiency, and a harder time getting the vehicle to start.

Can I temporarily remove furnace filter? ›

While your furnace can technically operate temporarily without a filter, you'll put it at risk of severe damages that are expensive to repair, in addition to jeopardizing the health and safety of you and your family.

Can you change a furnace filter while its running? ›

To Change Your Home Air Filter, You'll Need To Turn Off Your Furnace. To prevent the HVAC unit from turning on while you are changing the filter, make sure you turn the thermostat to the “off” position. This will help protect your HVAC system from loose debris or maybe a loose filter fitting escaping into the duct.

Can I take out my air filter in my house? ›

Remove the filter and shake vigorously outside to dislodge as much dust and dirt as possible. Rinse the filter lightly with soapy water, then rinse with clear water until clean. Scrub the cover in the soapy water, then rinse and dry with a microfiber cloth. Air-dry the filter thoroughly before replacing it in the unit.

How long can an air filter be out? ›

How long can you go without changing the air filter? The longest you should go without changing your air filter is the recommended 90 days. However, if replacing your air filter is simply out of the question for an extended period of time, going beyond 90 days is not going to cause irreparable harm to your AC system.

How long can you leave an air filter out? ›

There's no upper limit to how long you can leave it on; in fact, you get the most out of it if it's left on all the time since indoor air quality constantly changes. Ultimately, leave your air purifier on as needed. You may choose to turn it off during certain periods of the day, such as if you're leaving the house.

What happens if you run AC with dirty filter? ›

A dirty filter restricts the air flow into your HVAC systems air handler. This restricted air flow places additional strain on the air handler fan motor and could, over time, burn out the motor and cause your system to overheat and ultimately fail.

Will AC stop cooling IF filter is dirty? ›

Dirty air filters cause your AC to operate at a lower efficiency which means it does not cool your house as well as it should, and can end up costing you more money in the long run.

Will cleaning my AC filter make it colder? ›

Q: Does cleaning the AC filter make it colder? In a sense, yes. A clogged AC filter can trap cold air inside the air conditioning unit, preventing it from circulating through the ductwork and into the home. Replacing the filter improves that air flow, thereby allowing colder air to make its way inside.

Will AC TURN OFF IF filter is dirty? ›

Over time, the air filter draws in pet dander, dust, dirt, and other contaminants. That's its job. However, if the fibers get too clogged with debris, the HVAC system can't pull air through the filter. Eventually, this can cause the system to shut down.

What happens if I remove air filter from furnace? ›

Without a new air filter, the furnace will overheat every time it starts up again. This is referred to as short cycling. Dirty furnace filters cause your furnace to work harder than it should due to a decrease in airflow. The harder your furnace works, the quicker its parts will wear out and need repairs.


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