Air conditioning and furnace filters remove the dust, dander and allergens that float around in the air you breathe, so it’s important to change them every 30 to 90 days. Some of the most common filters you can purchase are below.

• Fiberglass filters: This is the most basic kind of flat filter that slides into place inside an AC unit. They’re an affordable option, but the least effective at trapping dust and allergens.
• Pleated filters: These are regular fiberglass filters with added surface area thanks to the pleats, or accordion-style folds across the filter. They work a little bit better and are only slightly more expensive than flat fiberglass filters.
• Electrostatic filters: These filters use electrostatic charges to attract particles in the air to stick to the surface of the filter. They’re highly effective at trapping dust and allergens.
• HEPA: True HEPA (High Efficiency Particulate Air) filters must be proven to trap 99.97% of all airborne particles greater than 0.3 micrometers in size. That makes them the very best available, so we recommend them for families with allergies or breathing problems.