Shopping for an Air Filter: They’re Not All the Same

Air filters need to be changed at least once a month. Regularly replacing your filters helps maintain your indoor air quality and keeps your HVAC systems working efficiently. Clogged and dirty filters obstruct air flow and force your air conditioner or heating to work harder than it needs to. The American Society of Heating, Refrigeration and Air Conditioning Engineers estimates that dirty filters can reduce efficiency by as much as 10 percent.

When shopping for an air filter, keep in mind that there are many different types to choose from. The amount of dust and particulate matter that a filter can block varies. The smaller the particles it can block, the more effective the filter. To find out how effective a particular filter is, check its minimum efficiency reporting value rating (MERV).

Fiberglass air filters

• These are some of the cheapest air filters. They’re also among the least effective. Fiberglass air filters are intended to protect HVAC units; they do little to improve your air quality.
• Polyester and pleated air filtersThese air filters are more expensive than fiberglass filters but are far more effective. They trap up to 45 percent of particulate pollutants.

High-efficiency air filters

High efficiency particulate air (HEPA) filters can remove as much as 85 percent of airborne particles. Although not intended for ordinary residential use (they’re designed for use in environments that need to be kept dust free, such as hospitals), these filters are sometimes suggested for the relief of allergies and respiratory disorders such as asthma. HEPA filters can be too restrictive for some systems, however, potentially obstructing airflow.There are also washable air filters, designed to be cleaned and re-used. Most HVAC experts regard these as very poor, and suggest avoiding them.

Make sure that the filter you choose is appropriate for your system. Check the manufacturer’s instructions before you buy.

To find out more about shopping for an air filter, contact Sobieski Services, Inc. Our goal is to help educate our customers in Delaware, Pennsylvania, Maryland and New Jersey about energy and home comfort issues (specific to HVAC & plumbing systems).

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