What’s the Difference Between MERV and HEPA Filters?

HVAC filter

In the United States, the average person spends 90 percent of their time indoors. So improving your indoor air quality represents a major step towards improving your health and quality of life. But it’s still easy to get confused by terms on air filters for your HVAC (heating ventilation and air conditioning) system. Here we’ll cover the difference between HEPA and MERV filters and what’s best for your system.

Understanding MERV Ratings

What Are MERV Filters? The term MERV stands for Minimum Efficiency Rating Value. It’s a scale developed by the American Society of Heating, Refrigeration, and Air-Conditioning Engineers (ASHRAE) to measure how effective air filters are at removing air pollutants. What are MERV ratings on filters? The ratings range from 1-16, with one being least effective and 16 being most effective. This is what else you should know.

  • Measures efficiency. Most HVAC systems will have a MERV 8 filter. However, the Environmental Protection Agency (EPA) recommends homeowners use a MERV 13 or better for improved indoor air quality. A MERV 13 removes 75 percent or more of bacteria-sized particles.
  • Relies on the HVAC capacity. Upgrading to the finest filter won’t make a difference if your system is unable to support the filter. Because finer filters have more layers for the air to travel through, they slow the airflow. Systems may try to work harder to maintain a certain airflow, either damaging the filter or the machine.
  • Correct sizing is important. Choose a perfect fit for your filter replacement. If you try to fit a filter that is too big for your system, you’ll have to crush it. If it is not big enough, air will slip past it without being filtered.

If your HVAC system cannot handle a MERV 13, choose the highest rating it can handle. You can always add an air purifier to augment it, if necessary.

Related Content: When Should I Replace My HVAC Filter?

Reduce Bacteria and Viruses with HEPA Filters

First, what are HEPA filters? An acronym for High-Efficiency Particulate Air, HEPA filters help eliminate contaminants the size of bacteria and viruses from your home.

HEPA filters capture even smaller contaminants than MERV filters, making them ideal for helping reduce the bacteria and viruses that can make your family sick. HEPA-filtered air removes 99.97 percent of air pollutants between 0.3 and 1.0 microns.

If your HVAC system doesn’t work with a HEPA filter, you can still improve your air quality using a portable air purifier. in fact, it’s good to have an alternative way to filter your air than relying solely on your HVAC.

After all, the EPA estimates homeowners only run their HVAC 20-30 percent of the hours out of the year. An air purifier can help filter during the other 70-80 percent.

When to Change Your HEPA Filter

How long does a HEPA filter last? The answer isn’t exactly simple. Many are only meant to last a few months, and others are rated to last for years. A good rule of thumb is to inspect your filter every 3-6 months. If it shows signs of damage or is packed with too much dirt to clean, it’s time to exchange it for a new one.

Find Air Quality Experts in Montgomery, AL

With so much time spent indoors, purifying the air is an important part of keeping your home clean. Making sure you have the right filters in your system and adding a portable air purifier for better air quality can make your home healthier and less dusty. At AirNow Home Services, we offer quality installation, repair, and maintenance for your HVAC and air purifier systems. If you would like to improve your air quality, you can schedule service online or give us a call at (334) 384-6050.