Actual size: 33 x 56 x 0.75 inches
Pleated air filters suitable for furnaces, ACs and residential HVAC systems
MERV 8 filters remove up to 90% of common household particles including dust mites, pollen, pet dander, and mold spores. These filters provide basic air quality for standard homes without allergies.
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MERV 8 air filters are ideal for homes seeking improved air quality and standard filtration. These filters are best in homes where pet dander is lower and there are no risks of outdoor pollution or construction. MERV 8 air filters provide sustainable air filtration without a high efficiency system in place. They capture up to 90% of particles and are generally used in family homes and smaller offices.
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Check the label on your current filter or use a tape measure to get the exact length, width, and depth before selecting your size.
Nominal size
Nominal size is what you normally see printed on the label. This is usually a rounded size which is often not the true size of your filter.
Actual size
Actual size is the true size of the air filter, usually written in smaller font below the nominal size.
Measure your current air filter or the length, width, and depth of the opening slot to get the actual size. Round it up to the nearest whole inch to get the nominal size.
Installing 33x56x1 air filters couldn't be easier. Just make sure to align the arrow printed on the side with the airflow direction!
Remove the air filter from the package
Locate the arrow and point it in the direction of the fan
Slide the filter in to the slot of the central unit
For return grills, insert the filter into the grill, pointing the arrow inwards
For best indoor air quality, we recommend you change your filters regularly at different times depending on your situation.
Replace your air filter every 6 weeks to minimize the circulation of bacteria and allergens in the air.
Replace air filters every 2 months to reduce odors as well as pet dander and hair buildup in your system.
Replace your air filter every 2-3 months to reduce airborne particles and maintain cleaner indoor air.
Keeping your air filter replacement schedule in mind can be challenging to say the least. Make your life easier with Filter King's auto delivery.
You should replace most 33x56x1 air filters every 30 to 90 days depending on your specific needs and circumstances. In households with asthma or allergies, replace your air filter every 6 weeks. If you have pets, replace it every 2 months. If you have young children, replace it every 2 to 3 months.
Using the wrong size air filter can lead to poorer air quality and cause problems for your HVAC system. If the air filter size is too small, unfiltered air can bypass the filter and allow for dust to enter your HVAC system.
No, never cut air filters to fit your filter slot if you’ve ordered the wrong size. Cutting damages the filter frame and media, creates gaps for air bypass, and reduces filtration effectiveness. If you've ordered the wrong size, Filter King offers a 30-day money back guarantee, so you can easily return or exchange your filter for the correct size.
In many cases it may be worth the extra cost, although it largely depends on your specific needs and circumstances. Higher-quality 33x56x1 filters often provide better filtration, last longer, and protect your HVAC system more effectively, meaning that the investment pays off through better air quality and reduced system maintenance costs.
No, never run your HVAC system without a filter, even temporarily. Running it without a filter allows dust, debris, and particles to enter your system, which can lead to expensive damage to components like the blower motor and evaporator coils.
A MERV 13 33x56x1 filter may restrict airflow in some of the older or lower-capacity HVAC systems, while most modern residential systems should handle a MERV filter without issues. If you notice reduced airflow, longer heating/cooling cycles, or increased energy bills after installing a MERV 13 filter, consider changing to a MERV 11 instead.
MERV 8 filters