Reliable Heating & Cooling

What Happens If You Run a Furnace Without a Filter?

Most people know a clogged air filter is bad for their furnace. Bad filters restrict airflow and can make your home dustier. If your filter is extremely dirty, you might be tempted to just take it out for the time being. But that raises the question: What happens if you run a furnace without a filter? 

Short answer: nothing good. Furnace filters are extremely important, and running a furnace without one will cause all kinds of problems. Read on to learn more about why furnace filters are so crucial to your indoor health and comfort. 

Contact Reliable Heating & Cooling today for furnace repair in Holland, MI.

Bad Air Quality

Air quality is the main problem with running a furnace without an air filter. Furnace filters exist to capture any soot, dust, and other particles that might come through the furnace and your ductwork. Most furnace filters are good at this and can catch particles as small as three microns (0.003 mm) in diameter. 

If you took your furnace filter out, you’d probably first notice excessive indoor pollutants like soot and dust around your house, especially near the air vents. The excess dust and air pollution might also aggravate allergies or other respiratory conditions, like asthma. 

Damaged Equipment

Filters don’t just keep the dust out of your house and lungs; they also keep particulate matter out of the gears of the furnace itself. If you run a furnace without a filter, dust can quickly coat the furnace’s interior and start causing problems. For example, dust could cover the main burner unit, leading to pilot light problems. 

Similarly, dust and soot will coat your ductwork and potentially cause damage. Cleaning your ducts can help, but you’ll eventually need to get a new filter to stop any damage from occurring in the long run. 

AC Won’t Work

People talk about them as if they are separate, but your air conditioner and furnace use the same filter, so taking it out will also affect air conditioner performance. Running your air conditioner without a filter causes similar problems as running your furnace, including excessive dust and potential equipment damage. 

Potential Danger

Running a furnace without a filter might also increase the risk of fire damage. Dust and soot may collect near hot electrical components that could catch fire if temperatures get too high. Fire hazards are no joke, so keeping your filter in the furnace is in your best interest until you get a new one. 

Mold Growth

Running a furnace or air conditioner without a filter is a surefire way to encourage mold growth in your home. Moisture can become trapped in the dirt and dust deposits coating the inside of your HVAC and may start growing mold. A common sign of mold growth is a foul, musty smell coming from your ductwork. 

How Often Should I Change My Furnace Filter?

We recommend changing your furnace filter at least once every year. Ideally, though, you should change it once every six months. If you live somewhere with a high amount of dust or air pollution, you may need to change your filter every three months instead of six. 

What Kind of Filter Should My Furnace Use?

Manufacturers rate the filtration ability of a filter using a minimum efficiency reporting value (MERV). Filters with high MERV ratings can more effectively filter smaller and smaller particles. HVAC equipment might not work properly if you do not use the correct type of filter, so double-check with the manufacturer. 

Most residential furnaces will use a filter with MERVs between 6 and 13. Anything higher than 13 will have minimal effects on indoor air quality in your house. You may have heard of HEPA filters that allow for extremely precise filtering, but they are better suited to commercial operations and largely unnecessary for residential furnaces. 

How Can I Make My Furnace Filter Last Longer?

You will eventually need to replace a furnace filter when it’s too dirty to do its job. In the meantime, homeowners can do several things to prolong its lifespan and functionality. 

  • Ensure you are using the right type of filter for your system. A misfitting filter might age faster and have lower heating efficiency. Furnace filters that are too small might leave gaps that dust and other particles can get through. 
  • If you don’t already have them, consider switching to pleated filters. Pleated filters have a larger surface area, allowing them to capture particles more effectively. Clogs are also less likely with pleated filters. 
  • Don’t switch your HVAC system on and off frequently. The best way to run it is to keep it at a consistent temperature setting. Frequently changing settings can use more energy and create more dust in the air. 
  • Get in the habit of vacuuming your home frequently, particularly around vents. If you have pets, vacuum at least once a week to keep pet hair and dander out of your ducts and filters. 
  • If you use a washable filter, let it dry completely before putting it back into the furnace. A wet filter can be a breeding ground for mold and algae, leading to bad smells and aggravated allergies. 
  • Get regular professional furnace maintenance. A professional can tune up your machine and ensure it’s working optimally so the filter lasts as long as possible. 

If your furnace filter is extremely dirty, taking it out for a night or two may be okay. But running your furnace without a filter is not a long-term solution. Following our advice above will ensure your furnace works optimally.

#1 Heating and Cooling Services in Western Michigan

So, what happens if you run a furnace without a filter? It will start causing problems. And when you have furnace problems, Reliable Heating & Cooling is here to help. We have helped thousands of Michigan homeowners with furnace installation and repair. Contact us online or call today at (616) 201-3513 to schedule an appointment

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