Shipton's CleanAir Solutions Blog
6 Types of Air Filters and How to Choose the Right One
Do you remember back in the day when you said "air filter" and everyone knew what you meant?
Then the pandemic happened.
Suddenly it feels like you need an encyclopedia and a dictionary just to pick an air filter!
Now we all want air filtration in our homes and at work. But we are all confused about which air filtration system to choose.
In this post, meet the six main types of air filters, learn what each one does and choose the right air filter for you.
What Is Air Filtration?
The place to start when talking about air filtration is always with a universal working definition.
What IS "air filtration," exactly?
Air filtration is the process of removing airborne solid PMs (particulate matter) from the air we breathe.
What Airborne Particles Should You Be Worried About?
Particulate matter is a major culprit for,
- Eye and nose irritation
- Skin issues
- Breathing difficulties
- Lung disease and more!
There are five main types of airborne solid particulate matter that most of us worry about when it comes to respiratory health and air quality.
The most common chemical particulate culprits come from the pesticide, herbicide and insecticide industries or the bulk chemical industries.
Mineral solid particles may be generated by work sites or naturally through weather events and even natural erosion.
Crystalline silicate is one of the most common metallic particulates. Coal and cement are also common examples of particulate minerals.
Metallic particulates can include nickel, cadmium, beryllium, lead and other potentially toxic airborne solids.
Organic solids can include:
- Dust mites
- Human hair
- Skin flakes
- Pet dander
- Tea and coffee
The biohazard category of solid airborne particles almost needs no explanation. And yet the virus that causes COVID-19 is not solid. It is a liquid.
Here, the biohazard solids we are concerned about include bacteria, mould, fungi microbes etc. Essentially any tiny, solid particle capable of carrying a liquid or gaseous passenger, such as a CoV-SARS-2 droplet.
Micron Rating for Air Filters
What is a micron?
A unit of measurement.
Microns (sometimes also referred to as nanometers, which is a similar unit of measurement) become quite important when we are talking about air filter performance or air filtration system performance.
For example, how big (or small) is the virus that causes COVID-19? The overall droplet size ranges between 0.06 microns and 0.3 microns. The average droplet size is between 0.1 microns and 0.125 microns.
You may have heard that N95 masks filter out particles as small as 0.3 microns, which is larger than the sizes we just discussed. So how can N95 masks be effective at protecting against the airborne transmission of COVID-19?
It is because the droplet itself has to ride on a solid particulate to get from an infected person to a new host. This is what brings the average size up to around 0.3 microns and makes N95 masks an effective protective agent.
Keep these numbers in mind as we move into an overview of the six major air filter types so you can choose the type that best fits your needs.
Learn About 6 Major Types of Air Filters
Every day it seems like there is a new air filter or air filtration system on the market.
But underneath the hype, most of these systems and products will still find a home in one of these six major categories of air filters.
1. Pleated air filter
Pleated air filters, or pleated furnace filters, are made from cotton or polyester are a very common filter type used by most residential and commercial furnace systems. Typically pleated filters carry a MERV rating of between 5 and 13.
Pleated furnace filters are good at catching larger solid particulates.
Their main job is to keep these larger particles out of the inside of the furnace, where they could over time build up on the blower motor and fan blades, lowering efficiency and becoming a fire hazard.
2. Glass air filter
Glass air filters are arguably the most common furnace filters in use today.
Glass air furnace filters use fibreglass instead of pleats to do the same basic job, more affordably although somewhat less efficiently.
3. Media air filter
Media air filters are like amped-up pleated air filters. By increasing overall surface area, media filters can trap airborne particles inside the filter and trap more of them before needing to be replaced.
4. Electrostatic air filter
As the name suggests, electrostatic filters use static electricity as a magnet of sorts to attract and trap airborne solids. Both disposable and reusable types exist.
The downside is that electrostatic air filters do a better job of trapping very small particulates than they do of trapping larger common airborne irritants such as dust and ash.
5. HEPA filter
The HEPA filter was first developed during World War II. Today's HEPA air filters stay true to the original technology and it still works just as well.
MERV 17 or higher filters have the same capacity as a HEPA filter for capturing solid particles sized 0.3 to 1 micron to a 99.97 percent efficiency.
6. Ultraviolet light air filters
UV light filters use a synthetic band of UV-C light to purify the air. This is often termed "germicidal radiation."
While UV light air filters are great for purifying the air of liquids and gases, they don't do as effective a job on solids.
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