Koch BioMAX 24x48x5-7/8 99.97% HC HEPA Wood Frame with Gasket Downstream

Most pleated filters should be changed every 90 days. However, households with pets, allergies, or heavy HVAC use may need to replace filters every 30–60 days. Commercial and industrial sites may require more frequent changes based on conditions.

Yes! If you need a filter with an exact size—down to the 1/8 inch—we can help. Visit our Custom Size Filters page to get started.

We’ve got you covered with our Filter Fit Guarantee. If the size doesn’t fit your system as expected, reach out to our support team and we’ll make it right.

We’ve been online for nearly 20 years, and our team has over 50 years of combined HVAC experience. We sell American-made filters from trusted brands like AAF Flanders and Koch Filter—no cheap knockoffs or low-performance imports. We’re also a proud NAFA member, which means we’re committed to real air quality expertise and professional standards.

Yes. MERV 13 filters offer excellent protection against fine smoke particles and airborne irritants. For odors or VOCs (volatile organic compounds), we recommend filters with activated carbon. We also offer standalone air purifiers with HEPA and carbon stages.

Yes. In fact, we supply filters to schools, clinics, and government agencies nationwide. Many of our filters—especially MERV 10, 11, and 13—meet or exceed specifications for professional use. You’re getting professional-grade protection for your home.

Yes. Almost all of our filters meet or exceed ASHRAE standards and are manufactured under strict quality control. Many are used in hospitals, schools, and government facilities—so you can trust they perform as advertised.

Look for the size printed on your old filter or measure the filter slot in your system. We recommend rounding up to the nearest 1/8” for custom sizes. You can also visit our How to Measure Filters page for step-by-step help.

Absolutely. If you’re ordering for a business, property, or large facility, we’ll provide a quote and recommend the right products for your needs. Reach out to our Commercial Services team anytime.

MERV (Minimum Efficiency Reporting Value) rates how well a filter captures airborne particles. The higher the MERV rating (typically 1–13 for residential use), the finer the particles it can trap—from dust and pollen to bacteria and smoke. We offer filters from MERV 1–13 to match your system’s needs and your air quality goals. Learn More

Filters with higher MERV ratings are denser and can reduce airflow in systems not designed for them. MERV 8–10 is a safe choice for most homes. For MERV 11 or 13, ensure your system can handle the increased resistance or contact our team—we’re happy to help you choose the right balance of efficiency and airflow.

Not when matched properly. All of our filters are designed for low pressure drop and optimal airflow. If you’re unsure, contact us—we’ll help you choose a filter that your system can handle safely.

Yes. Filters with higher MERV ratings (10–13) trap smaller and more harmful particles like mold spores, smoke, bacteria, and allergens. They’re ideal for families, people with asthma or sensitivities, and anyone wanting cleaner, healthier air inside.