- Fiberglass filters: the least expensive, and least effective at trapping particulates.
- Pleated filters: these offer more efficient filtering due to a greater surface area and are excellent at increasing efficiency and prolonging the life of the A/C unit.
- Electrostatic filters: these use electricity to attract and trap charged particles. They are particularly effective at trapping dust particles, and significantly enhance efficiency and prolong the life of the A/C unit.
- HEPA: high-efficiency particulate air filters remove 99.97% of all airborne particles exceeding 0.3 micrometers in size – making them the best for trapping allergens.
To varying degrees, all air filters will remove mold spores and dust, but only the higher-end HEPA filters are effective at trapping bacteria and viruses. To choose the right filter for you, consider the system requirements, including the unit’s warranty, which may require the use of a specific size or type of filter to prevent voiding the warranty. Weigh these requirements against your health conditions (such as allergies or asthma), and your budget. Keep in mind the replacement cost, particularly if you live in a hot region where the A/C season is much longer if not year ‘round. Whichever filter you choose, make sure to replace it frequently or it will lose its effectiveness. Depending on where you live, air filters will need to be replaced once or several times a season (every 3 months) to make for a cleaner home, a more energy efficient and longer-lasting A/C unit, and less chance of allergies.