HEPA filters are an excellent choice for reducing particles such as dust mites, pet dander, pollen, and mold spores in your home. These filters are designed to effectively remove most allergens, dust, pollen, and mold from the air, but they will not eliminate viruses or VOCs. Mold can grow inside fibers, so it's essential to replace your air filters regularly every 12 to 18 months or when needed. HEPA filters were originally developed in the 1940s to protect workers in nuclear facilities from breathing irradiated particles in the air.
MERV stands for Minimum Efficiency Report Value and is a measure of how well a filter removes particles from the air. Studies have shown that filters with a MERV rating of 12 or higher can significantly reduce indoor fine particulate pollution and alleviate some respiratory ailments. Newer filter systems use ultraviolet (UV) irradiation light to kill germs, according to Jake Loiko, owner of Hawks Mountain Home and Property Services in Springfield, Vermont. Because dense HEPA filters trap most of the particles in the air, they tend to clog more quickly than traditional filters.
Additionally, allergens can enter the home through open doors and windows, so a single drafty window can allow millions of particles to enter the air; therefore, the use of HEPA filters cannot guarantee the removal of all allergens. Disposable filters are made of pleated paper or polyester that provide a larger surface area for filtering. This electrostatic air filter has a MERV rating of 12, making it sufficient for common allergens such as mold spores, pollen, and pet dander. Nordic Pure MERV 12 filters are available in many sizes, so you should be able to find one that fits the return vent opening.
With a high MERV rating of 13, this 1-inch electrostatic pleated filter can attract and capture microscopic particles. Other types of filters include electrostatic filters and electrostatic precipitators which use a small charge to trap particles. A HEPA filter must be able to remove up to 99.97 percent of contaminants with a size of 0.3 microns or larger using a dense mesh of fibers arranged in a specific configuration. Therefore, HEPA filters can capture up to 99.7 percent of all contaminants 0.3 microns or larger.