Can you get sick from not changing the furnace filter?

Author: Mrs. Marian Mayert  |  Last update: Sunday, June 22, 2025

While it may seem obvious, dirty air filters are one of the main causes of poor home air quality. “If your family seems to be getting more colds or having more nasal congestion than usual, it might be a good idea to take a look at your furnace filter,” said Ear, Nose and Throat specialist, Morgan Yost, DO.

Can not changing your furnace filter make you sick?

If an air filter becomes clogged, poor circulation will result. This could cause unwanted moisture to stick around and invite mildew, which is a pain to remove and can come with long-term health complications.

What happens if you don't change furnace filters?

Dirty HVAC air filters hinder airflow and make your AC system work harder. This forces it to expend more energy and raise your utility bills. The harder the system has to work, the higher your bills will be.

How long can you go without changing the furnace filter?

For 1- to 2-inch filters, replace them every 1 to 3 months. For 3- to 4-inch filters, replace them every 6 to 9 months. For 5- to 6-inch filters, replace them every 9 to 12 months.

What happens if you wait too long to change your air filter?

If you don't change your AC filter, it will begin to fail. It will no longer be able to filter the air properly, letting dust and contaminants get into the HVAC system. Dust jams the moving parts of an AC such as fan motors and valves. Airflow is restricted which creates a strain on the system.

How to FILTER All Dirt & Dust & Pollen From Your Home & SAVE 100's New https://youtu.be/8yzOdujnEjg

Is it bad to never change air filter?

As the system is working harder to get around clogged air filters, it can cause the entire system to overwork and eventually break. If this happens, you'll need to replace the entire system, which can cost anywhere from $4,000 to $12,000.

What happens if you forget to change the air filter?

When you forget to change your air filters on an often and regular basis, dust and other particles can start to build up, creating a clogged or dirty HVAC air filter that will have negative consequences on your home's indoor air quality.

Will my furnace be OK without a filter?

Your furnace can, technically, run without a filter. However, we strongly recommend you don't run your furnace without a filter for any length of time. With air constantly moving through your furnace and your home, dust and debris can quickly build up, even in a matter of minutes.

How can I tell if my furnace filter needs changing?

Signs Your Furnace Filter Needs Changing
  1. There is noticeable discolouration on the filter.
  2. You can see the buildup of dirt and dust.
  3. You find your home needs dusting frequently.
  4. It seems your HVAC system is cycling longer.
  5. You realize it's been several months since you've replaced your filter.

Can I change filter while furnace is running?

Step 1: Shut Off the Furnace

You should always avoid changing furnace filters while running the heating system, as various types of debris can enter the furnace — and you certainly don't want that to happen.

Is no air filter better than a dirty one?

Is no AC filter better than a dirty one? No. A dirty filter will slightly protect against some dust particles that will damage your AC system. Its better to have a dirty filter than having no filter.

Is not changing your furnace filter a fire hazard?

A clogged air filter can also increase the chances of a fire, further advancing the safety concerns in this home. Clogged air filters prevent furnaces from running properly and reduce the life of the system. The blower, heat exchanger, burners and other components are all crucial for heating your space.

Can I clean my furnace air filter instead of replacing it?

Cleaning an air filter only has two additional steps from replacing one. Again, the first step is to turn off the HVAC system. Find the service panel, open the furnace, and then locate your filter and remove it from the furnace. From here, you'll want to place it dirty side up and gently vacuum the large debris.

Can a dirty furnace cause sickness?

Respiratory Infections: When Your HVAC Unit Hosts Unwanted Guests. Dirty air ducts can foster the growth of harmful microorganisms, including bacteria and viruses. When these pathogens are blown into your living spaces, they can increase the risk of respiratory infections.

What are the symptoms of a dirty furnace filter?

Warning Signs of a Clogged Air Filter
  • Increased Energy Consumption. When home air filters are clogged, furnaces have to work harder to meet the desired temperature of the thermostat. ...
  • Higher Electric Bills. ...
  • Uneven or Poor Heating. ...
  • Short On/Off Cycles. ...
  • Indoor Air Pollution. ...
  • Dust. ...
  • Burning Smells. ...
  • Getting Sick.

Can a dirty air filter make you feel sick?

The airflow reduction of the air filter causes severe health issues like fatigue, headache, breathing difficulty, and cold. Bad air quality: You can't expect fresh air when your air filter is dirty. The air filter is designed to filter out the microscopic particles and lower the smoke's intensity.

How long can you go without changing furnace filter?

For example, a one inch furnace filter should be changed out every one to three months. A three to four-inch filter can last for six to nine months. If you have a thick five to six-inch filter, it can last from nine to twelve months.

Can a dirty air filter cause allergies?

Dirty Air Filters Spread Allergens

This is the case when you have dirty air conditioner filters. The air in your home is contaminated with dust, pollen, dander, mold spores, and other particles. Consequently, about 60% of asthma cases are caused by those particles.

What happens if you don't clean your furnace filter?

A dirty filter in your furnace will generally lead to the following consequences: The furnace can overheat and turn off as a failsafe. Your home won't achieve the warmth or comfort you want. You can severely damage your furnace's internal components.

Will my furnace shut off if filter is dirty?

If your filter becomes clogged, it can cause your furnace to shut off as a safety feature to prevent damage to the furnace. To fix this problem, simply replace your air filter on a regular basis. If you have pets, be sure to change your air filter more frequently.

What happens if you forget to put a filter in your furnace?

If you were to use your home furnace without an air filter, all that dust and debris could get stuck in your system and cause a rather large buildup. Over time, these buildups can clog and damage your system. To protect and extend the lifetime of your system, we recommend only running your furnace with an air filter.

Do I need to change my furnace filter if it doesn t look dirty?

If the air filters are clean then you don't have to spend time and money on a new filter! Well, that might not be good. Air filters being dirty shows that they are working correctly, and if they are clean, it can show that they might not be doing their job.

Can you damage a furnace by not changing the filter?

The danger of not changing the air filter in the house for a long time is that it will eventually lead to furnace damage. This means that the entire system will get destroyed by the excess heat. Replacing the entire system can cost you enormous amounts of money, and it's almost the same as buying a new HVAC unit.

What happens if you wait too long to change air filter?

You may notice a significant decline in HVAC performance, increased energy bills, and decreased comfort in your home. Additionally, delaying filter changes can lead to more extensive damage to your HVAC system, requiring costly repairs or replacement.

What would happen if you never changed your air filter?

This leads to a variety of issues for your HVAC system including system inefficiency, higher energy bills, inadequate air quality, and ultimately failure. If you haven't been swapping your air filters as frequently as you should, there's no time like the present to start practicing this crucial maintenance step.

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