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  • Writer's pictureSteven St Louis


The Truth about Furnace Filters

There are 7 commonly used furnace filter types:

HEPA filters

UV light filters

Electrostatic filters

Washable filters

Media filters

Spun glass filters

Pleated filters

Each of these filters has its own set of pros and cons, which vary based on your goal for your home. Some people need furnace filters that will keep the air free of allergens and other pollutants, while others just need a basic filter to get the job done.

The materials air filters are made of vary from fabrics to fiberglass. Filters are rated from 1-16, which tells you how well the filter will trap pollutants.

An example of things that are the size of a micron

Human hair- 80-100 microns

Pollen- 30 Microns

Dust- 10 Microns

Dust Mite feces- 9 microns

Pet Hair and Dander- 5 Microns

Smoke- 1 Micron

40-0.3 Microns are invisible to the human eye!

You might be wondering….


Not all filters are made the same, so choosing the right filter depends on what you need to purify from the air.


High-efficiency particulate air (HEPA) filters are the best recommendation for allergy sufferers or people with pets because they are able to remove at least 99.97% of airborne allergens and pollutants — including mold spores and dust that are as small as 0.3 microns. With a rating nearing 16 - HEPA filters provide the highest protection for your home. They are able to remove even the smallest microns or airborne particles, including tobacco smoke pollution and harmful bacteria.


The biggest pro of HEPA filters is how effectively they purify the air. The design of these filters makes it ideal for capturing larger pollutants, like pet dander and pollen. These filters are also cost-effective and only need to be changed every year.


While they’re great at ridding your home of most pollutants, there are still some pollutants that HEPA filters are helpless against. Fumes, gasses and odors are too small for HEPA filters, and pollutants like mold spores may settle on the filter itself, reducing its effectiveness and likely requiring replacement sooner than expected.


UV filters use short-wave ultraviolet light to kill bacteria and viruses. When air passes through the HVAC unit, the UV lamps disinfect it with germicidal radiation. UV filters are excellent for killing microorganisms that could be hazardous to your health, including mold spores.


The UV light used in these filters is able to kill tough pollutants like mold and germs, giving you exceptional indoor air quality to help prevent diseases and respiratory illnesses.


Though UV filters are great at eliminating bacteria and viruses, they are not as efficient when it comes to screening against pollutants like dust. This is why they are often part of a larger filtration mechanism, which includes HEPA air filters. The UV light is invisible to the human eye, and the lightbulbs generally need to be replaced every year, depending on the make and model of the HVAC system.


These filters keep particles from spreading throughout your home, making them one of the best choices for those who need a filter that can combat allergens.

An added bonus for electrostatic filters is they are available as disposable as well as reusable. When it comes time to change the filters, you can decide whether to wash and reuse them or toss them and get brand new ones.


Regardless of whether you choose the disposable or reusable option, these filters are some of the most cost-effective options on the market.


While this filter handles smaller pollutants, it may struggle to filter larger ones, such as dust or mold spores. This makes electrostatic filters a poor choice for people who have respiratory issues.


While certain types of air filters come with reusable and disposable options, washable filters are an environmentally friendly way to save money. The initial price of this air filter type for HVAC systems is high, but it will last for many years.

Pros: The best thing about a washable filter is you only need to buy it once, and it will likely last for the life span of your HVAC system. This makes washable filters extremely cost-effective and helps reduce waste.

Cons: For washable filters to continue doing, their job they need to be maintained regularly, which means removing and washing the filter and letting it dry fully before reinserting it. Failure to maintain a washable filter will reduce its effectiveness a damp filter will grow mildew and mold, which can make your indoor air quality worse.


Media filters are very easy to maintain and great for filtering bacteria and other small airborne pollutants. The filtered dirt is sealed into the filter, preventing it from being expelled back into your home. Media filters are also sturdy and cost-effective, needing to be changed as infrequently as once or twice a year.


These filters are popular for their low maintenance since they only need to be changed once or twice a year. They are great at filtration thanks to their increased surface area, and they trap pollutants rather than sending them back into the air.


Media filters need to be professionally installed, and they are ineffective when it comes to filtering odors.


These filters are not known for improving air quality since they are unable to strain very much and can only trap some dust and allergens. For this reason, these filters are not recommended for people who have respiratory problems and need a filter that will improve the indoor air quality.


The main selling point for spun glass filters is their price — they are one of the cheapest on the market. Spun glass filters are also exceptional at catching and filtering late debris, like lint and dust.


Because spun glass filters have a smaller surface area, they are ineffective in filtering smaller pollutants. This makes them a poor choice for those who live with asthma and other respiratory illnesses.


The pleats in these filters give them an advantage over non-pleated options because they increase the filter’s surface area for better filtering. Filters with more pleats will provide better filtering than those with fewer pleats, trapping even difficult allergens and pollutants, like pet dander and mold.


Pleated filters are also exceptional at catching the most debris


They are one of the more expensive filters on the market.

If you are wondering what filter is best suited for your home, health and family needs, contact our SS Plumbing & Heating Ltd for a free phone consultation!

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