You probably don’t think much about the air you breathe in your home, but maybe you should. That air can be filled with tiny debris- including dead skin cells, pollen, dirt, and bacteria, and breathing too of it much over time could be unhealthy. Fortunately, your home’s air filters trap these particles, helping keep your whole family healthy.

What exactly is floating in the air?

    • Dust – We see it on our tables and abandoned trinkets on our mantle, but where does dust come from?  The bulk of dust varies home to home, but basically dust is ‘anything that can flake off’ including dead skin cells, pet fur, food, dirt, pollen, pieces of books, carpet upholstery, debris from outside, etc. If not properly cleaned, mold, bacteria, and dust mites are all likely to inhabit dust and pollute your air.
    • VOCS – Your furniture, your belongings, and the building materials in your walls also give off gases. These are known as VOCs, volatile organic compounds. They are floating in the air and affect your air quality. You probably also are breathing in gases released from cooking and cleaning. In addition, pollutants can travel in from outside. You might even have mold if there is humidity in your home. 

You won’t necessarily smell or see any of these, and exposure to these particles is pretty much unavoidable. Over time, these compounds can build up in your system and lead to illness. That’s why air filters are so important. They can trap alot of the unhealthy particles. (They won’t however trap mold. You will need a separate treatment to get rid of the source of the moisture and remove the mold.)


What are air filters?

Air filters resemble rectangular cardboard frames filled with a material that looks and feels like pleated or woven coffee filters. When air is forced through the filter, the particles become trapped in the material. You’ll find air filters in your heating and cooling system, and as part of your furnace. Typically, a house will have one or two intake vents that require an air filter but you may have more depending upon the number of floors.  


One size does not fit all.

Air filters come in different standard sizes and thicknesses. The measurements are printed right on their frames. Check the size of your vent openings so you’ll know which ones to buy. Air filters work best when they fit snugly. That way air goes through it and doesn’t leak around it. However, you should not have to bend or crush the filter to make it fit. While filters range from about one to five inches in thickness, most HVAC systems are built for one-inch thicknesses.


What are air filters made of?

Air filters are made from various materials, which allows them to collect different-sized particles. Most filters are disposable but there are some that are considered permanent and can be cleaned and used again. Here’s what you might find at your local hardware store:

    • Disposable fiberglass: The most common type, this collects bigger particles. 
    • Disposable pleated: This is made of cotton or polyester, and is able to pick up large and small particles. It is the most affordable.
    • Disposable electrostatic: This type has electrically charged fibers to collect smaller particles. It is slightly more expensive than the disposable pleated.
    • Permanent electrostatic: This type is washable and can be reused. While you need to clean it regularly, you also will need to replace it every 6-8 years. It’s more expensive than disposable filters. 
    • High efficiency pleated: This type is thicker than many others, as much as 4-5 inches, which doesn’t work for a lot of systems. It can trap the smallest particles, and is more expensive. 


How good are they at trapping particles?

Air filters come with a rating scale that tells how well they trap particles. This rating is called MERV, short for Minimum Efficiency Reporting Value. MERV ratings were established by the American Society of Heating, Refrigeration, and Air Conditioner Engineers. 

    • MERV 1-4 provides the basic level for the lowest cost.
    • MERV 6-8 offers good filtration and is most commonly used in homes.
    • MERV 9-12 is above average and can trap smaller particles.
    • MERV 13-16 offers the highest quality and removes particles as small as 0.3 microns.

It’s important to note that the higher the MERV rating, the lower the airflow. That means your system will have to work harder, which could be more expensive and also lead to a shorter system lifespan. Consult a professional HVAC technician to provide a recommendation for your system and needs.


How to change your filters

Changing an air filter is quick and easy. Follow these steps. Use a ladder if the vent you are trying to reach is high up.

    • Turn off your furnace. 
    • Locate the filter compartment. Remove the door or service panel. 
    • Slide the old filter out and put the new one in.
    • Use a rag to clean any dust on the vent. 
    • Repeat with intake vents throughout your home.
    • Turn your furnace back on.


What if your filter looks clean when you go to change it? 

    • Check and make sure it’s fitting well with no gaps. 
    • Make sure it’s not upside down. Arrows should point toward the fan or your system.
    • Try a filter with a higher MERV rating to catch more.

How often should you change your filters?

A clean air filter makes your heating and cooling system more efficient. This can save you money, as much as $9-$22 a month. Manufacturers usually recommend changing your air filter every 60-90 days. However, if you have pets or allergies, you may want to replace them more frequently. Create a calendar alert so you will know when to change yours.

Pro Tip: Hold your filter up to the light. If you can’t see light through it, it is time to change it.

In addition, you may want to add pet-friendly plants that also help with indoor air quality. Finally, make sure to protect your home with the right insurance for added peace of mind. After all, your home is your greatest investment.



This article is furnished by California Casualty, providing auto and home insurance to educators, law enforcement officers, firefighters, and nurses. Get a quote at 1.866.704.8614 or

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