Filter for a home with allergies

A furnace filter can capture some airborne pollen, dust, and pet dander as air circulates through your HVAC system. For many homes, a compatible pleated filter with a higher MERV rating is a useful option—but choosing a rating your system cannot handle may restrict airflow. Check your equipment instructions before moving to MERV 13.

Choose a filter that captures allergens without restricting airflow

MERV ratings indicate how effectively a filter captures particles of different sizes. Higher ratings generally capture smaller particles more effectively, but they can also make it harder for air to pass through. The right filter is the highest-rated option your furnace or air handler is designed to use—not automatically the highest rating available.

MERV 13 may be appropriate if your equipment manufacturer allows it. If the manual lists a lower maximum, follow that guidance. When the rating is unclear, ask an HVAC professional to check the system rather than experimenting with a more restrictive filter.

A properly sized filter matters just as much as its rating. Read the size printed on the existing filter and confirm it matches the filter slot. Do not force a filter into place or use one that leaves gaps around the edges; air can bypass the filter instead of passing through it.

Check the system before buying MERV 13

Look in the furnace or air-handler manual for the permitted filter type or maximum MERV rating. If you have a filter grille or a thick media cabinet, check its specifications too. Filter depth and the amount of filter surface area affect airflow, so two filters with the same MERV rating may not behave identically in different systems.

After installing a new filter, make sure it sits flat and that its airflow arrow points toward the furnace or air handler. Watch for signs that airflow may be inadequate, such as noticeably weaker airflow from vents or unusual equipment behavior. A filter alone may not be the cause, but if these signs begin after changing to a higher rating, switch back to the manufacturer-approved filter and contact a qualified HVAC professional if the problem continues.

Replace the filter and reduce allergens at the source

Follow the replacement interval specified by the filter or equipment manufacturer. Check the filter more often at first, especially during heavy heating or cooling use, or if you have pets or significant dust. Replace it when it is visibly loaded or at the stated interval; a clogged filter can impede airflow. Do not wash a disposable filter.

A furnace filter only captures particles that pass through the HVAC system. It will not remove allergens already settled on surfaces or prevent outdoor pollen from entering the home. Regular cleaning, keeping pets out of sleeping areas if that helps your symptoms, and addressing moisture or dust sources can complement filtration. If symptoms are significant or persistent, discuss them with a healthcare professional.