How Do Air Filters Work

Air filters or air purifiers are a part of many modern ventilation systems and as single-room units and are essential for the efficient circulation of air in a building or home and more importantly, for keeping the air quality at maximal levels and making sure a minimum of pollutants, allergens, irritants, and other potentially harmful microparticles out of the air. Others include air purifiers that work with central air units to filter the entire home. Below, we’ll discuss how air filters work at home.

What do air filters do in your home?

Air filters comprise part of or the entire functionality of most home air purifiers (some are just referred to as air filters, but most are marketed as air purifiers) on the consumer market. Their filtration systems aim to improve indoor air quality and health in various living spaces by removing organic compounds, particulate matter, dust mites, pollution, and gaseous pollutants. 

Particles, fumes, pollutants, bacteria, allergens, or other unwanted airborne substances must be removed from the air. How the different types of air purifiers manage this can vary a great deal. Some air purifiers have multiple air filter functions. Others can be installed as whole-house air purifiers. They all, however, are designed to work either as standalone models or in conjunction with a home’s ventilation system to provide cleaner air, as defined by the manufacturers.

Kinds of Air Filters

There are several different common kinds of air filters available, some of which perform the same job with different technology, and some of which are designed to handle multiple different kinds of air filtering.

• HEPA filters– High-efficiency particulate air filters made of fiberglass and varying amounts of activated carbon material and are considered among the most effective at filtering out microparticles that can affect people with respiratory conditions, making them great for commercial air purifiers as well. They are effective at trapping up to 99.97% of particles including molds, spores, pet dander, and dust, and the US Department Of Energy, which recommends HEPA filters amongst all other kinds, recommends they be changed every six to twelve months.
• UV Light Filters – These filters use ultraviolet light to destroy bacteria, fungus, molds, and other living pollutants on a molecular level, borrowing technology from medical facilities. While they can be effective at that task, UV light filters can’t tackle airborne dust, dander, and other such materials.
• Electrostatic filters- These filters use an electrostatic charge to capture dust and other airborne particles via magnetism. They vary in effectiveness, but one advantage is that many are washable, making them slightly more economical than others.
• Fiberglass Air Filters- Non-HEPA fiberglass air filters are made to be disposable and thus low-maintenance. Fiberglass air filters are the most economic of filter types but often aren’t effective enough at trapping dust and other irritants to be a good choice for people with respiratory illness, and are usually more effective at protecting air conditioners than filtering the air.
• Washable Filters- Washable filters are designed to be both economically and ecologically sound while still being effective at trapping dust, dander, and other airborne irritants and pollutants. They can vary in the material they’re constructed with but are meant to be a permanent solution as they do not require replacing if properly cared for. The disadvantage is that they must be cleaned thoroughly and completely dried regularly, making them higher maintenance than most filter types.
• Activated Carbon Filter- These filters are often used in conjunction with another filter type because they’re effective at eliminating or neutralizing gasses, fumes, and smoke, making them good at fighting odors, including from smokers, though not effective at capturing dust and other particles. They are a common addition to a HEPA filter purifier.

In addition to identifying the various filter types, we also highly recommend keeping an eye out for these metrics that will tell you whether your air purifier is working.

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