Filtering areas in air conditioning systems can become a very dangerous point for the reproduction of microorganisms and bacteria, if it is not given proper management. But, what will be better than an air conditioning system with an excellent well-managed filtering area. Undoubtedly, breathing in a building that has it is a real pleasure and a great benefit for health; taking into account that the World Health Organization estimated in 2006 that 4.6 million people died a year from causes that could be attributed to air pollution.
With the development of constant research and the evaluation of various proposals and prototypes, it can be said that there are filters for everything and for all budgets. However, given the large number of materials available on the market, many times the best criteria for choosing one or the other is not available.
To determine which filter is the most appropriate for certain conditions, a solution has been found widely accepted in the industry and that is currently used in a standard way, I refer to the MERV exams, Minimum Efficiency Reporting Value, or minimum efficiency report value, which as its name says, report the minimum capacity of detection of micro-particles that a filter has.
The filters that are tested by this standard, MERV, are rated from 1 to 15 and according to the capabilities of the same, it is said that the filter is of low, medium, high or absolute MERV rating.
Low-rating filters are those ranging from 1 to 4. These filters do not reach 20% efficiency and stop only particles between 3 and 10 microns. They are generally washable filters made of polyester or fiberglass.
In the MERV mid-rating category, we talk about those who are left with a rating between 5 and 8. These filters provide efficiencies between 20% and 65%. Some of the most popular in this category are pleated filters, which are commonly used in normal air conditioning installations, without high levels of indoor quality requirements.
The high category receive MERV rating between 9 and 15, these guarantee between 85% and 95% of minimum efficiency when capturing the particles. This category is the one that has the widest range of products on the market. Some of the best known filters are those of bag, and the rigid ones, the latter can be built of plastic, metal, cardboard or wood. We can also mention in this category the box type, and the miniplisados.
From grade 15, MERV tests cease to be the norm and open the way to absolute detection filters that reach minimum detection efficiencies of 99.97%, some of the best known filters in this category are hePA (High Efficiency Particulate Air), and ULPA (Ultra Low Penetration Air). Due to their high detention, these filters are generally used in places where indoor air quality must be rigorous, such as in the case of clinics and hospitals and microprocessor development plants.
