Problems with running your AC without filter

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The air filters are a vital part of the air conditioner and though your air conditioner can run without them, it is not a wise thing to do. The filters are responsible for blocking the dirt and debris from entering your air conditioner and giving you clean and healthy air to breathe. In the lack of filter, the dirt and debris collect inside your system that leads to decreased quality of air in your home and serious damage to your system after some time. You can face various problems with running your AC without a filter, which we are going to describe in detail for you in this article. 

Problems with running your AC without filter

When the air is sucked inside the air conditioner, the filter works as a barrier in front of the vent and prevents the dirt and debris to get inside the system along with the air. Not having a filter can greatly affect the indoor air quality and the functioning of the air conditioner in the long run.

The top recommended filters for your air conditioner are:

  1. Air Purifier Whole House Uv Light in Duct for Hvac Ac (Air Conditioning) Duct Germicidal Filter + 2 replacement bulbs
  2. Original PURE AIR UV AIR Purifier Whole House Dual UV UVC Light in Duct for HVAC AC Duct GERMICIDAL Filter
  3. Trophy Air 20x25x1Pleated Electrostatic Air Filter Replacement | Washable | 6 Stage HVAC | Micro Allergen Defense, Healthier Home Environment | AC Furnace Air Filter Replacement | Made in the USA
  4. Air-Care 16x20x1 Silver Electrostatic Washable A/C Furnace Air Filter – Limited, Never Buy Another Filter!! – Made In the USA
  5. Flanders PrecisionAire 10155.011212 12 by 12 by 1 Flat Panel EZ Air Filter
  6. Purolator/Indigo Fiberglass Filter 20x20x1 (12 Pack)
  7. AIRx Filters Allergy 16x25x1 Air Filter MERV 11 AC Furnace Pleated Air Filter Replacement Box of 6, Made in the USA
  8. Aerostar Allergen & Pet Dander 16 3/8×21 1/2×1 MERV 11 Pleated Air Filter, Made in the USA, (Actual Size: 16 3/8″x21 1/2″x3/4″), 6-Pack
  9. Aerostar Home Max 20x20x1 MERV 13 Pleated Air Filter, Made in the USA, Captures Virus Particles, 6-Pack

Following are some problems with running your AC without a filter:

  1. Condensate drain problems:

    When the air passes through the evaporator coil of the air conditioner, it converts the humidity present in the air into water. This condensed water drips down into the drain pan and then passes through the drain pipe, to the exit pipe. The filter of your AC keeps the dirt and debris away from the condensate drain and prevents it from clogging. A clogged drain is unable to pass the condensed water outside and as a result, causes water damage to your AC. If left unchecked for long, this water damage can lead to serious permanent damage to your air conditioner.

  2. Air quality problems:

    The filter of your air conditioner is responsible for improving the air quality of your home by capturing the dirt, dust, and other pollutants present in the air. When there is no filter in your AC, the dirt and other particulates just pass through the air vents and remain inside the air of your house for you to breathe in. The impurities suspended in your indoor air due to lack of filter decrease the air quality of your home and it can cause some health issues, such as:
    a) Symptoms of flu
    b) Nose and throat irritation
    c) Itchy and watery eyes
    d) Increased chances of an asthma attack
    e) Respiratory disease

  3. Frozen evaporator coils:

    The evaporator coils of your air conditioner are responsible for converting the refrigerant running in the system from liquid to gas by absorbing the heat from the air. This gaseous form of the refrigerant is then transferred to the condenser and converted back into liquid form, before releasing the heat outside. If you have dirty filters in your AC or no filter at all, dirt and debris will collect inside the system. This dirt and debris stick to the evaporator coils carrying the refrigerant, causing the system difficulty for the evaporator coils to absorb heat. This inability to absorb heat will cause the condensation to become too cold and lead the evaporator coils to freeze.

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    This issue of frozen evaporator coils will lead to some serious issues such as:
    a) Increased energy bills: The frozen evaporator coils are unable to absorb heat efficiently, causing your air conditioner to run for longer periods to cool your home. The system running for a longer period will lead to increased energy usage and thus increased energy bills.
    b) Damaged compressor: The compressor is located in the outdoor unit of your air conditioner and is responsible for pumping the refrigerant throughout your system. But when the evaporator coils freeze, it becomes difficult to transfer the refrigerant in the system. When you keep running your air conditioner with frozen evaporator coils, it will put more pressure on the compressor resulting in damage to the compressor of your system. Now, the compressor is an important and expensive part of your AC and your system will not function without a compressor. 
    c) Less conditioned air: Frozen evaporator coils cause the air conditioner to produce less conditioned air. When your evaporator coils are frozen, the air coming out from your air vents will be very less and cooler than normal. It will affect your air conditioner in the long run and can even cause serious damage to the system.

  4. Ductwork problems:

    The dirt and debris that stick don’t to the evaporator coils travel through your ductwork, due to lack of filter. The debris traveling through the ductwork is trapped inside it, causing moisture to build up inside the ductwork. This accumulated moisture in the ductwork is the perfect place for molds to grow. After that, whenever you run your air conditioner, the mold spores will circulate inside your home with the air. These mold spores in the air of your home cause several health issues such as allergies, asthma, etc.
    Image credit: Wikimedia Commons


The filter of your air conditioner plays an important role in providing you clean, healthy air and helping your system to perform its work efficiently. Therefore, it is a must to use a filter in your air conditioner. You can choose the best air filter for your air conditioner based on various factors like size of the filter, types of filter, MERV ratings, etc. Get the best air filter suitable for your air conditioner and home and breathe in the air of peace and relief.

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