Is a MERV 13 Filter Right for Your HVAC System?

Many businesses consider upgrading their HVAC filters to MERV 13 or higher to improve indoor air quality, and ASHRAE and other building-health organizations recommend MERV 13 where systems can handle it. A MERV 13 filter captures at least 85% of particles 1.0 to 3.0 microns in size, which includes much of the fine dust, smoke and respiratory aerosols that cheaper filters let through.

But is a MERV 13 filter right for your system, or could it cause more problems than it solves?

The Added Stress on Your HVAC System

MERV 13 filters use denser media than standard filters, which increases the resistance your system's fan has to push against. Many commercial and residential systems were designed for MERV 8 filters. Installing a more restrictive filter in a system that wasn't built for it can reduce airflow, strain the blower motor and coil, and shorten the equipment's life.

Even if the equipment holds up, your utility bill may not. A more restrictive filter makes the fan work harder, and over a large building, the added energy cost of MERV 13 can add up to hundreds or thousands of dollars a year. For a homeowner's view of the same trade-off, see MERV 8 vs. MERV 11.

An Alternative: HEPA Filtration With Its Own Fan

A HEPA (High-Efficiency Particulate Air) filter goes well beyond MERV 13. A true HEPA filter captures at least 99.97% of particles 0.3 microns in size, the hardest size to filter, which is why HEPA filtration is standard in hospitals and cleanrooms. HEPA performance is beyond the top of the MERV scale.

The catch is airflow: HEPA media is far too restrictive to use as an ordinary HVAC filter. The practical answer is a HEPA unit with its own dedicated fan, either a portable air scrubber or a central air purifier connected to your ductwork. Your main system keeps its normal airflow while the HEPA unit cleans the air alongside it. Abatement Technologies Central Air Purifiers work this way, and some models add germicidal UV.

So What's the Right Filter for Your System?

Your HVAC system needs proper airflow to perform. MERV 13 and HEPA filters capture far more fine particles than standard filters, but the wrong filter in the wrong system can do real harm. Before upgrading, check your system's manual or ask your HVAC contractor what filter resistance it's designed to handle. If MERV 13 is too restrictive, a dedicated HEPA purifier is usually the better path.

Not sure what your system can handle? Contact us with your equipment details and we'll help you find a safe, effective solution.