Can I Run My HVAC System Without a Filter?


So it is time to change your filter in your HVAC system, you notice it is extremely dirty and definitely needs to be switched out asap. But you do not have a new, clean filter around the home. So should you keep the old dirty one in, or just run the system without a filter at all? I mean you don’t want the dirty filter doing harm to the home right?

So, you want to run your HVAC without using a filter, but you are a little skittish on going through with it? Should you wait and change your filter when you have a new one? Can you run your HVAC without using a filter? You should never run your HVAC system without a filter. The system can run without one, but could cause major damage to your HVAC system and will create low air quality throughout the home.

Reasons to always use a filter in the HVAC system:

  1. It will keep the unit motor clean from debris
  2. It will keep the unit clean as a whole
  3. It will keep the coils from getting damaged from dust particles and small foreign objects
  4. Wont allow dust and buildup to enter the ducts
  5. Will keep air quality high and make sure it doesn’t become hazardous

If you want to find the best HVAC Filters, click here.

The good news is we have all the details on exactly how this could affect your HVAC system and what you can do to keep yourself from running into costly repairs in the future.

Why Do We Need a Filter?

First, it is important to understand why you have the filter in the first place. Let’s think of your air filter as your HVAC systems first line of defense. When you go to bed at night you probably wouldn’t leave your front door wide open, right? Well, not installing a filter to your HVAC system is a similar idea. The filter is input into your system to stop all dirt, debris, and small foreign objects. Just as if your front door is closed, unwanted intruders are not able to invade your home. If the filter is not in place the dirt and debris is free to penetrate throughout your home through the duct work system as it will easily pass through the HVAC unit. More importantly this is where damage and costly repairs begin to pile up! That is the last thing any homeowner wants! Let’s get into how we can prevent costly HVAC repairs and how we can prolong the life of air conditioner and furnace units.

Air Conditioner Specifics

For air conditioners specifically we see that many homeowners ignore the recommended duration of use on air filters. This, like skipping an air filter altogether, is going to do damage to the unit in time. The ac works by intercepting the air inside the household at the vent. The air then moves through the ac unit passing wet cylinders that are filled with a substance called freon. The freon is what makes your air condition pump out the cold air. When the vent intercepts the household air with no filter it is a guarantee that dust, small debris, pet hair, skin cells, you name it and it’s going to make its way into your system. The cylinders that contain the freon are a costly repair if they begin to deteriorate due to foreign object build up in the system. The simple fix for this is to avoid freon tube damage by changing your HVAC filter at regular recommended intervals.

Furnace Specifics

For the furnace system or the air condition we see that both units have a high rate of transferring foreign debris from their units into the ventilation systems. Like the ac unit, the furnace also depends on the filter to stop the flow of foreign bodies of dust, debris, and other small ailments that may pass through a vent. The unit will suffer damage from the objects and may also push them into the duct work of the home. This is not only costly but can be dangerous.

Ventilation Issues When No Filter is Used:

  • Debris build up in ventilation and ductwork
  • Debris and dust travels through home
  • Debris build up may allow mold to form over time
  • AC and furnace unit will not work properly

As mentioned above there are semiserious problems that can occur if the filter is not used with relation to the ventilation system throughout the home. The larger amount of dust and debris that is passed into the furnace or ac unit, the larger amount of work your unit will have to do to maintain the proper temperature of the home. This can ultimately lead to overworking the unit and wearing it out from unnecessary prolonged activity to keep a content temperature. This will eventually hit the homeowner in the wallet as well!

The HVAC unit may also be passing the dust and debris into the ventilation system and there it will either pass through to the rest of the home, as stated before or it can start to build up in areas throughout the system over time. If this happens mold spores will begin to grown in these areas. This is especially true in more humid climates although they can and will accumulate anywhere. The more humid the climate the more rapidly they will produce. Unfortunately, it is then possible for the spores to spread in the home when the unit is pushing them back through the vents into the home. Mold is a very real fear for many homeowners who have heard very devastating events that can happen if mold takes over in your home. That is why it is so important to use and change air filters regularly. Your home and your family’s health are dependent on it!

If all of this talk about mold and debris causing damage to your heater and ac units is giving your a headache then please read on! We have a simple and manageable solution. It is never to late to insert a filter to your system, and if you are unsure of the last time that your HVAC filter was changed it is inexpensive enough that you can go ahead and install a new filter today!

Filter Change Schedule:

  • Small filters of 1 or 2 inches can be changed every season (quarterly)
  • Mid sized filters of around 4 inches can be changed semi annually (2 times a year
  • Large filters of around 5 inches can be changed yearly
  • If you see buildup on the filter go ahead and change!
  • You can find easy to use and effective filters here. Just choose the right size for your home.

Pro Tip

If you want to be a HVAC honor student! Always write the date that the filter was inserted into your unit on the filter itself. You can use a sharpie or pen and simple write 3/1/20 if you input the new filter on the 3rd of March in 2020. This way if you are feeling forgetful you can check the unit and see when you should replace the filter on your heater or ac. You can also add the date that you will need to replace your filter to your calendar. Then you will ensure that you are doing your due diligence to avoid any costly mistakes or hazardous air quality that could have been a simple and inexpensive fix! Remember to always follow the instructions on your HVAC unit and the filter instructions and call a professional if you feel that anything seems unsafe!

Final Thoughts

An HVAC system will run without a filter, however running it without one is a huge mistake. No filter will result in a damaged unit and poor air quality in the home. Not using a filter is a costly mistake that will result in spending more money and possible health issues.

Also if you need help on how to change your filter, watch the video below:

Related Questions

Do I need to turn the furnace off to change the filter? Yes, you need to turn off the furnace to change the filter. This will ensure that while you are changing it, nothing goes into the furnace that isn’t supposed to.

Will the furnace shut off if the filter is dirty? No, the filter will continue to run even with a dirty filter.

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