There are lots of air filters on the market at many different price points. San Diego homeowners often ask if there’s really any difference between them. To better understand the various types of filters available, it’s important to understand MERV ratings.

The Minimum Efficiency Reporting Value scale expresses the amount of airborne particles, and the size, that a filter is capable of removing from the air. Harmful particles removed by filters include dust, pollen, bacteria, viruses and mold spores. MERV is an excellent tool for comparing the effectiveness of filters and for matching the filter to your needs.

The MERV scale ranges from 1 (least effective) to 20 (most effective). Higher-level filters, HEPA filters or those at 17 to 20 on the scale, are used in industrial applications such as clean rooms, labs and hospital operating rooms to provide the highest level of indoor air quality possible. Filters above 16 are much denser and can restrict airflow.  Use of these filters is not recommended for residential use unless designed and installed by a trained professional. These installations are generally very expensive and require a great deal of maintenance.

According to the EPA, filters with a MERV from 7 to 13 work almost as well as HEPAs, are much less expensive and practical for home use.

Homeowners are well-advised to use the most effective filters compatible with their home comfort systems and their budgets. Filters should be inspected bi-monthly and replaced or cleaned as needed , especially during peak seasons.

Be sure to consult your manufacturer’s instructions or speak to your local HVAC expert if in doubt about the proper filter for your needs and your system.

Have questions about air filters? Contact the pros at ASI Hastings Heating and Air Conditioning. We’re happy to advise local residents on filters, ventilation and indoor air quality issues. Our company provides complete HVAC services, and you can learn more by visiting our website. Let us be your resource for home cooling, energy efficiency and heating information – give us a call anytime.