When shopping for filters or purifiers, you’ll run into acronyms like MERV, HEPA, and CADR. Understanding what these mean can help you make smarter choices—especially if you’re dealing with mold, allergens, or chemical sensitivities.

• MERV (Minimum Efficiency Reporting Value) is used for HVAC filters and ranges from 1 to 16. The higher the number, the more particles the filter can capture. For most homes, MERV 13 or higher is ideal—it can trap things like smoke, pollen, mold spores, and even bacteria.
• HEPA (High-Efficiency Particulate Air) filters are used in portable purifiers and must capture 99.97% of particles down to 0.3 microns. They’re excellent for allergy, asthma, and mold concerns.
• CADR (Clean Air Delivery Rate) isn’t a filter type—it measures how fast a purifier delivers clean air. We covered this in Section 1, but it’s worth remembering that higher CADR = faster and more effective cleaning.

Stick with filters that are clearly rated and third-party tested. If a device doesn’t list its MERV, HEPA, or CADR rating, that’s a red flag.