Why You Need a 4‑Inch Air Filter Instead of a 1‑Inch

Living in Portland, you have probably noticed that the air quality isn't great. If you’re like most Americans, you spend about 90 percent of your time indoors working, spending time with your family, and doing recreational activities. But you may not know that your indoor air can contain 2 to 5 times more pollutants than outdoor air.

According to the Environmental Protection Agency, modern homes are more efficient but are also more likely to limit airflow coming indoors. The airtight homes combined with people using personal care products, pesticides, and home cleaning products can negatively affect indoor air quality. Contaminants can then lead to health issues like eye, nose, throat irritation, headaches, dizziness, or even respiratory disorders.

One of the easiest ways to keep your indoor air clean and contaminant-free is to use and maintain your HVAC air filters. In this blog, you’ll learn:

  • What does an air filter do
  • Why you should use 4-inch air filters instead of 1-inch ones
  • How to change your air filter

No matter what brand of HVAC system you have, Four Seasons Heating & AC has the right filter for your home. Schedule a service appointment online or call us at 503-538-1950 to keep your filters—and your home—clean and healthy.

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What Does an Air Filter Do?

Four Seasons technician changing out an air filter

The air filter in your HVAC system prevents contaminants from circulating throughout your air and settling on your household surfaces. It keeps contaminants from entering your HVAC system and being recirculated in the cooled or heated air pushed out. They not only keep the air in your home clean, but they also protect your system from getting clogged by dirt and dust.

Air filters can trap the following contaminants:

  • Pet dander
  • Hair
  • Dust
  • Lint
  • Smoke
  • Smog
  • Bacteria
  • Allergens
  • And more!

HVAC air filters are made of either pleated cloth or spun fiberglass and enclosed in a cardboard frame. They can cost between $4 and $25 depending on the thickness, MERV rating (which stands for Minimum Efficiency Reporting Value), and manufacturer.

The MERV rating is the primary rating system for HVAC filters. It demonstrates the filter’s ability to trap pollutants from passing through and circulating in your home.

For example, a filter with a MERV 6 rating is a basic one that can trap dust, lint, and most pollen. A MERV 8 filter can trap everything that a MERV 6 can trap and mold and dust mites.

If you get a filter rated MERV 11 or greater, you’re ridding your home of smoke, pet dander, smog, viruses, and bacteria, too.

Why you should use 4-inch air filters instead of 1-inch ones

Stack of air filters

The most common air filter you can purchase for your HVAC system is 1-inch thick. Depending on your system, the dimensions of your filter could be:

  • 10 x 10
  • 14 x 20
  • 16 x 24
  • 18 x 30
  • 14 x 24

All air filters have their sizes marked clearly on their cardboard frame to make it easy to purchase the right-sized replacement. The 1- inch and 4- inch filters cost about the same for a replacement, but you’ll save money every year with the larger, more efficient filters because they don’t need frequent replacement to keep your air clean.

If you have a 1-inch air filter, it must be replaced every 1 to 3 months to stay clean. When the filter gets too dirty, it will restrict airflow to your HVAC system, possibly leading to a motor burnout and causing your system to fail. That’s a costly problem caused by something relatively inexpensive to maintain.

In some circumstances, your air filter may need more frequent changes. For example, if you have pets, a large home, renovation projects, or your household has a smoker or somebody with allergies, your home has a greater level of air pollutants that need filtering out.

If you have a 4-inch filter, it needs to be replaced every 6 to 12 months. Because it is four times as thick as a 1-inch filter, it has a much greater surface area for catching household pollutants. These larger filters also typically come with higher MERV ratings and can capture more contaminants (e.g., pet dander, smoke, allergens, and bacteria) than a 1-inch filter.

How to Change Your Air Filters

Clean vs. dirty air filters

To change the filters in your home, follow these steps:

  1. Loosen the fasteners holding the outer metal grille to the vent opening and remove the cover. You can use your hands if you have wingnut fasteners, but you may need a screwdriver. If your filters appear dirty or brown, it’s time to replace them.
  2. Reach in and pull out the dirty filter from the vent opening space.
  3. Take the new air filter out of any extra packaging. Look for the arrows on the cardboard that indicate airflow direction.
  4. Position the airflow arrows towards the wall and insert the new filter into the duct opening. Make sure it is snuggly in place.
  5. Replace the metal grille cover and tighten the fasteners to secure it back in place.

Need help choosing and changing your air filters? Let Four Seasons Heating & AC do the dirty work.

Call us at 503-538-1950 or schedule an appointment online today. One of our certified technicians will arrive within a 2-hour service window, install your new filters, and inspect your HVAC system as a courtesy- usually within an hour.

Our 100% satisfaction guarantee backs up everything we do, so you know we’ll get the job done right.

Schedule Service Today!

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