The American Society of Heating, Refrigeration and Air Conditioning Engineers (ASHARE) recommends a MERV 6 or higher for household air filters. Most people use a MERV 8 filter, which is capable of removing contaminants with MERV 8 to MERV 13.Hospitals usually use MERV 14 to MERV 20. When it comes to air filters for HVAC systems, there are three main options: pleated filters, fiberglass filters, and washable reusable filters. Each type has its own advantages and drawbacks.
Most air filters are 1 inch thick, but some systems can accommodate filters 2 to 5 inches thick. In our tests, we found that the thicker the filter, the better it works and the longer the replacement intervals. Ultraviolet (UV) filters use short-wave ultraviolet light to kill bacteria and viruses. When air passes through the HVAC unit, UV lamps disinfect it with germicidal radiation.
UV filters are excellent for killing microorganisms that could be hazardous to health, including mold spores. However, they can also transform oxygen into ozone, which can be hazardous to health in high amounts. Electrostatic filters create static electricity that acts as a magnet for dust and other particles in the air. The magnetism is strong enough to prevent these particles from spreading throughout the house, making them one of the best options for those who need a filter that can combat allergens.
Electrostatic filters are available both disposable and reusable. Washable filters are an eco-friendly way to save money in the long run. The starting price of this type of air filter for HVAC systems is high, but it should be considered as an investment that will last for many years. Washable filters need to be maintained well to ensure they work as they should.
Media filters provide the same level of filtration as a high MERV filter, but do so without the negative consequences of airflow or static pressure. Media filters have a larger surface area, which successfully avoids significant static pressure and provides better filtration. They are very easy to maintain and ideal for filtering bacteria and other small airborne contaminants. When it comes to air filters for HVAC systems, it's important to consider not only the size of the filter but also its MERV rating.
This rating indicates how good an air filter is at trapping dust particles and preventing them from circulating back into your home. A MERV rating of 1 is the worst rating, while a MERV rating of 16 is the best. A media filter lives between the return chamber and the furnace, so the system may need some type of reconditioning if it is not already configured for one. They have more surface area than a filter, allowing for better airflow and you only have to replace them once a year.