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AC Furnace Air Filter
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Product Description

Filter Size: 18x20x4

Actual Size: 17.5×19.5×4

Actual Size Fraction : 17-1/2×19-1/2×4

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18x20x4 Air Filters

Elevate your indoor air quality effortlessly with our premium 18x20x4 Air Filters, available for convenient online purchase exclusively at Custom Filters Direct. Tailored to fit HVAC systems with precision, these filters redefine air purification, ensuring a healthier and more comfortable living environment. Explore the exceptional features that make our 18x20x4 Air Filters the optimal choice:

Key Features:

  • Nominal Size (18x20x4): Perfectly designed to fit your HVAC system, our filters provide an exact fit for enhanced efficiency. Enjoy the peace of mind that comes with a filter solution that caters precisely to the specific dimensions of your space, ensuring optimal performance.
  • Lasts up to 3 Months: Extend the life of your air filter with our 18x20x4 model that lasts up to three months. This extended lifespan not only promotes consistent air quality improvement but also reduces the hassle of frequent replacements, offering a convenient and efficient filtration solution.
  • Supercharged Pleated Panel Filtering Media: Crafted with supercharged pleated panel filtering media, our filters are a powerhouse in capturing fine airborne allergens. From dust and smoke to dander, mold, pet dander, and dust mites, these filters act as a formidable magnet, efficiently attracting particulates as effectively as dust on a TV screen.
  • Up to 30 Times More Efficient: Experience superior allergen capture with our 18x20x4 Air Filters, which are up to 30 times more efficient at trapping airborne particles compared to ordinary fiberglass filters. Invest in a filtration solution that exceeds industry standards, providing your living space with cleaner and fresher air.
  • Uniform Pleat Shape: The uniform pleat shape of our filters is not just an aesthetic feature; it enhances dust holding capacity while maximizing airflow. This thoughtful design ensures optimal performance, contributing significantly to the overall effectiveness of your air purification system.
  • Proudly Made in the USA: Trust in the quality of our products, as all our air filters are proudly manufactured in the USA. Benefit from superior craftsmanship and reliability, knowing that your indoor air purification needs are met with a product crafted with precision and care.


Upgrade your air filtration system with confidence. Purchase the 18x20x4 Air Filters from Custom Filters Direct today and immerse yourself in the transformative difference of superior air quality. Breathe cleaner, live healthier – make the choice for optimal indoor air purity now!