The Science of Air Filters

Nerdy filter nerd facts from nerdy filter nerds.

4 Things Worth Knowing

Air Quality

Filters improve your home’s air quality by removing particulate matter and toxins.

Filter Options

There are a lot of them. FilterEasy makes sure you have exactly what you need right when you need it.


A rating scale for the efficacy of an air filter. Mostly confusing, we’ll dig into that later. Just know our filters are in the sweet spot for most homeowners.


Regular filter changes means cleaner air for you and your family, decreased energy consumption, and an extension to your HVAC’s lifespan.

Air Quality

Poor air quality has a big impact on the health of you and your home. Letting it get worse can lead to some serious complications.

A couple enjoys clean air by the fire

Indoor Air Pollution

When you think “air pollution,” what comes to mind? The foggy smog over LA? Pollen clouds coating southern skies in sickly pale yellow? Outdoor air pollution is a real concern, sure, but the air inside your home can be up to 5x worse.1 Yeah. Air circulation isn’t what it used to be! Modern homes are built tighter to improve energy efficiency, which is great. Unfortunately, natural air doesn’t flow in, so the air in our home stays funky. So, you know, maybe crack open up a window or two from time to time.

There’s a lot of concern around harmful chemicals in the house, and for good reason! Over 2,000 chemicals are released into the market every year, spread over thousands and thousands of products. Chemicals that make things smaller, better, cleaner, you know the drill. They aren’t all bad, but they aren’t all great either. It’s never a bad idea to read your product labels.

Are you familiar with Sick Building Syndrome? Sounds made up, right? 100% real. The World Health Organization defines SBS as a medical condition where people in a building suffer from symptoms of illness or feel unwell for no apparent reason.2 WHO studies have linked mucous membrane irritation (eye, nose, and throat irritation), neurotoxic effects (headaches, fatigue, and irritability), asthma and asthma-like symptoms (chest tightness and wheezing), skin dryness and irritation, gastrointestinal complaints and more as a few symptoms to SBS. That’s about as real as it gets right there.

A woman gives her home a fresh coat of paint

Indoor Air Quality

IAQ is quite the buzzword these days. The EPA defines it as the air quality within and around buildings and structures, especially as it relates to the health and comfort of building occupants.3 It’s not a full-on red alert public health issue, but when you factor in poor outdoor air quality, it’s a bit more problematic. Outdoor air quality is measured by the EPA on the AQI, more on that here. AQI fluctuates, but even when it’s trending well, there’s a handful of nasty Volatile Organic Compounds ready to strike.

According to the EPA, VOCs are emitted as gases from certain solids or liquids. VOCs include a variety of chemicals, some of which may have short- and long-term adverse health effects.4 They are things like benzene or formaldehyde, and they hide in all sorts of things. Plenty of common paints contain aliphatic hydrocarbons, ethyl acetate, glycol ethers, acetone. Formaldehyde hydes (get it) in paint as well, but it’s also in ceiling tiles and adhesives. Benzene is a known carcinogen and is usually found in cigarette smoke and smoke from a wood burning fire. So if you’re painting, smoking, or adhesing (not a real word, but roll with us here), filter your air! Open a window, make sure you’re circulating the indoor air, and make sure you have a fresh air filter installed. Wink.

Air Filters

More options than you'd think

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Air Filters
Pleated Air Filters
Air Filters
Cost Inexpensive, Less than $5 $10 to $30 Each $50+
Material Fiberglass Polyester or Cotton Paper Blend Usually Aluminum
Replacement Frequency Every 30 Days Every 30 to 90 Days Every 5 or so years
Efficient at Catching Large Debris Yes Yes Yes
Efficient at Catching Small Particles No Yes No
Recommended for People with Allergies No Yes No
Maintenance Level None, just replace None, just replace High, requires cleaning
Reusable No No Yes


MERV who?

MERV stands for Minimum Efficiency Reporting Value, a rating scale from 1 to 20. The higher the MERV rating, the more effective the filter will be at trapping airborne particles and toxins.

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MERV Rating Particle Size Ranges Typically Seen in Controlled Contaminants
1–7 3–10 µm Low End Residential, Industrial Workplaces, Commercial Buildings Pollen, sanding dust, textile fibers, carpet fibers, paint overspray.
FilterEasy Sweet Spot
8 (LiteAllergen) 3–10 µm Better Residential Everything above and mold, spores, dusting aids, cement dust.
11 (MircoAllergen) 1–3 µm Superior Residential Everything above and large bacteria, pet danger, smaller dust particles, and auto emissions.
13 (SuperAllergen) 0.3–1 µm Superior Residential Everything above and all bacteria, cooking oil smoke, smog, tobacco smoke, and droplet nuclei (sneeze).
14–20 <0.3 µm Hospitals, cleanrooms. Commonly called HEPA (MERV 16) or UPLA (17–20) filters. All combustion smoke, carbon dust, viruses.

Higher MERV ratings put more strain on your HVAC system, and most homes don’t need anything beyond a MERV 13. Our filters hit the sweet spot of MERV 8, 11, and 13, keeping your home filtered well without expensive energy bills.

Our Filters

We offer three different filters, rated MERV 8, 11, and 13. LiteAllergen (MERV 8) is the entry level filter. It gets the job done better than a cheap fiberglass filter, and you can swap it every 3 months. The next step up is our MicroAllergen (MERV 11) filter. If you have pets or allergies, this one’s a must. Lastly, we have the SuperAllergen (MERV 13) filter. This one’s great if you or someone in your home suffers from other respiratory conditions, and it filters out some of the smallest particles like cooking oil smoke or cigarette smoke.


Air filters are incredible. Unpopular opinion? Maybe. Do we stand by it? Absolutely. Here’s why: regularly changing your air filters means you’ll use less energy. Your HVAC unit loves it when it doesn’t have to push your air through a mess of disgusting particle junk, so it won’t run longer just to keep your house at the optimal temperature. The less it pushes itself, the less likely it is to breakdown! That saves you money on costly repairs. With all that money you save you might be able to take that much needed vacation! Or at least treat yourself to a spa day.

Changing those filters also means the air in your home is cleaner and healthier for you and anyone else under your roof! MERV 11 filters can actually reduce the risk of infections from droplet nuclei by 60% (MERV 13–16, that number’s up to 64%). What are ‘droplet nuclei,’ you ask? Great question. You know when someone’s sick or sneezing all the time? They aren’t just sneezing air; there’s all sorts of nastiness flying around. That nastiness? Droplet nuclei. Glad you asked?

So change those filters, people! We don’t want to hear “I’m too busy” as an excuse, either. With FilterEasy, we’ve made it as convenient as possible for you. Just sign up, select your filter size and quantity, choose your quality level, and schedule your deliveries. Every shipment reminds you to change your filters, and that is pretty incredible.


You know, when it comes to air filters, there’s a surprising amount of information to absorb. We kinda love this stuff, but we know not everyone cares! You’re still reading though… so maybe you’re just as weird as we are? That’s good, we like weird. Here’s some more weird info for you, weirdo.

Familiar with the term pressure drop? This is a metric that measures the impacts different air filters have on your home’s air flow. A filter is typically installed in a return to intercept the air intake going to your HVAC system. Too high of a pressure drop and your HVAC unit will overwork itself, that’s no good. Using a pleated filter increases the surface area, giving you a low pressure drop while still hitting good MERV ratings. Good being anything MERV 8 or higher. Anything under a MERV 8 is basically worthless. Unless you enjoy breathing old sneeze particles and litter box dust.

Another term comin’ atcha: arrestance. This measures the ability of an air filter to remove synthetic dust from the air. Basically, we want our filters to arrest any sort of synthetic gunk that doesn’t belong in our lungs. This is tested with a specific kind of dust, standardized by the HVAC wizards of ASHRAE. The magical mixture is 72% “Arizona Road Dust,” 23% powdered carbon, and 5% cotton linters (fibers commonly used in paper making). It’s delightful. Tastes awful though.

“Useful” Information

Love doing trivia with your friends? Great! Here’s some info somewhat related to air particles that will literally never come up. Ever.

Ever heard the term brownian motion? It’s the random, zig-zaggy motion of particles in suspension, like in a liquid or a gas. This happens when there’s a thing with a thing - you know what? That’s too much science, even for us. If you wanna learn more, we suggest you head to Wikipedia or a phriendly neighborhood physicist. Ooh! But what about agglomeration, that’s a fun sounding word! This is when airborne particles collide and create larger particles. Gee, really thought that would be more exciting.

Oh well, one more for you. Van der Waal force, any ideas? Well, these are the forces of attraction between molecules, named for Johannes Diderik van der Waals. He was Dutch, won the Nobel Prize in Physics in 1910, and had a sweet beard.

The End


Well, you made it. Welcome to the bottom of the page, dear reader. We hope the journey was worth it. However did you find the time to read this far? Oh, so silly of us, you must be using FilterEasy to automate the delivery of your air filters every couple of months! You’re welcome for that free time back, although we really think you oughta read something a tad more interesting, how about this, this, or this?

Have any questions for us? Think we didn’t cover enough? Think we covered too much? Whatever you might need, we’re here to help. If you’re super into reading all the scientific information about air filters but you haven’t given us a shot, why not start a free trial today? Clearly you appreciate the fine art of air filtration.