MERV 8 vs MERV 11 Air Filters: Which Is Right for You?
Air filters are an essential part of maintaining healthy indoor air. They help capture airborne particles like dust, pollen, and pollutants that can cause respiratory problems and reduce air quality. But how do you choose the best air filters for your needs?
In this article, we explain how air filters are rated, the difference between MERV 8 air filters and MERV 11 air filters, two of the most popular filter ratings for domestic use, and help you to choose the best rating for your HVAC air filters.
MERV 8 vs MERV 11: The Short Explanation
The main differences between MERV 8 and MERV 11 filters are the size of the airborne particles they can capture and their impact on airflow and pressure within an HVAC system.
A MERV 8 filter captures most household dust, pollen, and pet dander. Filters rated MERV 8 are an excellent choice for homes without air quality concerns like allergies or respiratory health complaints.
A MERV 11 filter, in contrast, provides enhanced filtration by capturing a greater percentage of smaller particles, including vehicle emissions, bacteria, and mold spores. They may be a good choice for homes with residents suffering from allergies or respiratory problems or those who prefer cleaner air than lower-rated filters can provide.
However, while more effective, MERV 11 filters slow air flow through HVAC systems and make them work harder. You should verify that your system supports higher-rated filters before installing them.
What Are MERV Air Filter Ratings?
MERV is the Minimum Efficiency Reporting Value, a rating system designed to rank the effectiveness of air filters on a scale from 1 to 16 (or up to 20 for HEPA-level filters). The MERV rating is based on testing that considers the efficiency with which a filter collects particles of varying sizes:
- E3 focuses on larger particles, ranging from 3 to 10 microns. This includes household dust, mold spores, pollen, pet dander, and dust mite debris.
- E2 covers a range of 1 to 3 microns, targeting particles such as bacteria, fine dust, and auto emissions.
- E1 represents the filter’s efficiency at capturing extremely small particles between 0.3 and 1 microns. These include particles like smoke, viruses, and certain types of dust, which are often the most challenging to capture due to their minute size.
A micron is one-millionth of a meter. A human hair is about 70 microns, and bacteria range from around 0.2 to 2 microns. A higher MERV rating means that a filter more efficiently captures smaller particles. Filters are tested to determine their efficiency at capturing particles in each size range and then given a score based on their efficiency across those ranges.
What Does MERV 8 Mean?
A MERV 8 air filter captures at least 20% of particles measuring 1 to 3 microns and at least 75% between 3 and 10 microns. Particles of this size range from dust and pollen to mold, some bacteria, dust mite debris, and pet dander.
Many domestic air filtration applications use filters with a lower rating than MERV 8, which is generally considered the higher end of what is needed in a standard domestic system.
MERV 8 filters offer excellent filtration without putting too much strain on the HVAC system. However, they may not be ideal for homes filled with multiple pets or individuals who struggle with very sensitive allergies or respiratory conditions.
What Does MERV 11 Mean?
MERV 11 air filters capture over 65% of 1–3 micron particles and over 85% of 3–10 micron particles. In addition to being more efficient than M8 filters for larger particles like pollen, a MERV 11 filter will capture smaller pollutants like auto-emissions, lead dust, some types of smoke, and fine dust particles.
Higher-rated MERV 11 filters are often used in high-end residential and industrial HVAC systems. They may be an excellent choice for homes with pets, people dealing with respiratory ailments, or houses in heavily polluted areas.
It’s worth noting that, compared to MERV 8 filters, denser MERV 11 filters can constrict airflow, affecting the efficiency of your HVAC system. They are also more expensive and will increase initial and replacement expenditures.
Is MERV 8 or MERV 11 Right for You?
Deciding on the right filter for your home involves considering a handful of interrelated factors, including the following:
- Individual home needs
- Lifestyle considerations
- Air quality requirements
- Allergies and respiratory conditions
- HVAC system requirements
Generally, MERV 8 filters offer a reasonable balance between filtering efficiency, parts costs, and HVAC system maintenance costs for an average household or office.
However, if your situation demands cleaner air than a MERV 8 filter can provide, a MERV 11 filter may be a suitable alternative. Your choice will ultimately depend on the types of particles present in your surroundings as well as airflow needs, budget constraints, and health concerns of the occupants.
Is MERV 8 Good Enough?
For homes with minimal air quality concerns, allergies, or asthmatic conditions, MERV 8 filters are usually more than adequate, often recommended for households without pets and far from significant pollution or smoke sources.
In terms of cost-effectiveness, MERV 8 filters offer sufficient air filtration for many homes while costing less and lasting longer before they need replacing. Plus, they are more likely to be compatible with standard HVAC systems without significantly reducing air circulation efficiency or putting additional strain on the system.