The air filter plays an important role in maintaining indoor air quality. It needs to be replaced regularly, or the entire HVAC system could stop working properly. But before you go ahead and replace the HVAC filter, take a moment to learn about the different types of filters.
1. Air conditioner filter
The standard, plastic mesh filter doesn’t have a unique name. It may be referred to as a washable filter.
This type of filter only traps dust, insects, and hair to protect the cooling coil and prevent problems with efficiency and airflow. Understand that this type of air filter is designed to protect the air conditioning system. It is incapable of filtering out bacteria and viruses that may aggravate symptoms of asthma and allergies.
2. Media air filter
Also referred to as panel air filters or fiberglass air filters, media air filters have a cage structure that holds a piece of filter media made of polyester fiber. The standard filtration grade of media air filters is around G4 or MERV7.
This type of filter can trap mist, fog, and pollen to purify the air.
3. Pleated air filter
Most central AC systems in the US use pleated air filters, which have the same filtration grade as media air filters. However, some have a higher level of filtration, removing bacteria, mold, and dust mites from the air.
This type of filter is more expensive to maintain and can be referred to as disposable air filters. They typically need to be replaced after three to four times of washing.
4. Bag air filter
Also known as pocket air filters, bag air filters have a filtration grade of around F7 or MERV13. This type of filter cannot be washed and needs to be completely replaced every one or two months, depending on how dirty it is.
5. Electrostatic air filter
The electrostatic air filter has three sections: a pre-filter section, a charge section, and a collector section. The filtration quality of this type of air filter is around F8 or MERV15. The electrostatic air filter has negatively charged plates that attract positively charged particles, helping remove contaminants from the air.
6. HEPA filter
HEPA filters are the highest-rated filters on the market, with a filtration grade around H11-14 or MERV 17-20. They are used in operating rooms of hospitals, semiconductor assembly rooms, and laboratories.