MERV stands for Minimum Efficiency Rating Value and is a scale that ranges from 1 to 16. The lower the number on the MERV scale, the lower the filtering efficiency. Both MERV-12 and MERV-13 have excellent capabilities to trap larger contaminants, with MERV-13 slightly excelling at capturing the smallest contaminants. The U. S.
Department of Energy recommends MERV 13, while ASHRAE recommends MERV 6 or higher and LEED recommends MERV 8 as a minimum. In general, filters with higher MERV ratings capture higher percentages of particles, as well as smaller particles. A filter with a higher MERV rating can block microscopic particles, such as smoke molecules, due to its tighter mesh fabric. The Minimum Efficiency Report Value (MERV) rating for an air filter measures how effectively the filter prevents dust and other contaminants from passing through the filter into the air stream.
Surgeries have a variety of Merv filters and HVAC systems use Merv filters; in both cases, they don't use fiberglass. In general, filters with a MERV 16 rating or lower are considered HVAC system grade filters for residential, commercial, and general hospital use. When you have a Merv filter 13 and higher, it's more similar to the material you'd find in an n95 dust mask. A MERV filter 13 is likely to help if the goal is to prevent droplets from passing through.
A high-merv filter media, blasted with compressed air and inserted into a pocket of a DIY face mask between two layers of cloth, could suffice. Washing an alcohol could very well be creating some strange chemicals, unless you are just washing cotton; in this case, sunlight could be used to disinfect them, even though it could break the tall Merv filters a little and release unintentional, perhaps dangerous, chemical degassing. A Merv high activated carbon filter could be your best option between you and any other exotic chemical action you have going on. The MERV rating system ranges from 1 to 20, with the highest rating (20) being the rating used for filters in places such as hospitals. Air filters of different sizes will have different prices, the same goes for the MERV rating of the filter.
Choosing the right MERV rating for your needs can be tricky; however, understanding what each rating offers can help you make an informed decision. If you're looking for a filter that can block microscopic particles such as smoke molecules, then a higher MERV rating is recommended. On the other hand, if you're looking for a filter that can trap larger contaminants then either a MERV-12 or MERV-13 will do the job. Ultimately, it's up to you to decide which one is best for your needs.