If you suffer from allergies, asthma, or other respiratory conditions, you may want to use a filter with a MERV rating of around 10 to 12. These filters are effective at trapping particles as small as 1 micron, such as car exhaust, pollen, and mold spores. MERV ratings are determined by the effectiveness of a filter to capture particles of different sizes. Specifically, these ratings measure the ability of a filter to capture 12 particles of various sizes from 0.3 to 10 microns (µm) in diameter that were created in a laboratory environment. For reference, a human hair measures approximately 50 µm, and the smallest particles that can be seen by the human eye are around 40 µm.These 12 particles are divided into three different size ranges (E1, E2 and E3) and four subranges that exist within each range.
The first range, E1, includes particles with a size of 0.3 to 1.0 µm. E2 includes particles with a size of 1.0 to 3.0 µm, and E3 encompasses particles with a size of 3.0 to 10.0 µm. These MERV ratings are divided into four groups. The MERV 9-12 range is considered the best for residential use due to its high efficiency at trapping tiny particles. If the filter is too dirty or too resistant, it can cause airflow problems that impair efficiency and performance.
To determine resistance, filters use the MERV rating system. In short, the higher the MERV rating, the more resistant the filter will be. The MERV rating is essential for finding the right air filter for your home. For residential furnaces, filters range from 4 to 12 on the MERV scale. A basic MERV 4 filter is probably the cheapest option but won't trap certain small particles (such as dust mites and pet dander) that might be in your home.
If your family has health problems or allergies, then you should look for a high-efficiency filter with a MERV 11 or higher rating. But for most homes, a MERV 7 or 8 filter could be the ideal choice between performance and cost. If your home's HVAC system is unable to handle MERV 13 filters, opt for the next highest possible rating. Filter technology has advanced significantly over the years, and MERV ratings are designed to help us determine the most effective and efficient air filter options for heating and cooling systems and more. Since higher speed filters allow less air to flow through the oven, it's important to check if your system has a maximum MERV rating. While higher MERV ratings are more effective for air quality, they can damage your HVAC system.
While the air filter is designed to control the amount of unwanted air particles entering your home, your filter's MERV rating is meant to show you which filter is best for your home. In general, air filters with higher MERV ratings remove a higher percentage of airborne contaminants and therefore improve your home's indoor air quality. If you use a higher MERV rating that traps more particles, you may need to change the filter more often. If your oven's MERV rating is too high, it can force your oven to work too hard and leave it vulnerable to damage. It's best to comply with oven manufacturer's recommendations or consult an HVAC professional to determine exactly which MERV rating is best for your specific system.
If your HVAC has a permanent split condenser blower, a higher MERV rated air filter will interfere with it and cause lower airflow. In general, filters with higher MERV ratings are more effective and improve air quality but they are also more expensive. The higher the MERV rating on a filter, the less dust particles and other contaminants can pass through it. Filters with higher MERV ratings should be changed more frequently (at least every three months) to avoid restricted airflow that can cause your system to operate inefficiently or even damage it. With the lowest MERV rating (1-), your filter will still capture pollen, dust mites, cockroach debris, sanding dust, spray paint dust, textile fibers, and carpet fibers. A MERV rating of 13 to 16 is considered hospital-level air quality so it's unlikely that your home will need more than that. When buying oven air filters, don't confuse MERV with other rating systems that may appear on packaging (especially in large home improvement stores).