A Merv 8 air filter is an efficient way to trap most indoor particles that can cause respiratory problems or weaken people with asthma and allergies. It is the most common type of filter recommended by HVAC technicians, and it can be up to eight times more effective than fiberglass filters. A Merv 8 filter is sufficient for the average home, as it covers common allergens such as pollen and mold, as well as products normally used in homes such as cleaning products and hairspray. It can block up to 90% of particles, but it doesn't capture all allergens.
For people with allergies, pets, or who live near smoke pollution, a Merv 11 air filter is the ideal choice. It is more expensive than a standard filter, but it is worth the extra efficiency. Merv 11 filters are better at eliminating odors and can filter a large percentage of fine particles. In some cases, a higher MERV rating such as Merv 13 may be necessary.
The Merv rating system provides a standard for comparing air filters from different manufacturers. Choosing a filter with a MERV rating that is too high for your unit can cause it to work too hard and wear out equipment faster. Strict building codes and an increase in foot traffic generally mean that commercial properties must opt for a filter with a higher MERV rating. However, air filters with such a high rating, MERV 16 to MERV 20, are generally only found in hospitals and nuclear power plants where air filtration is essential.
For most homes and commercial buildings, filters with a MERV rating between 8 and 13 will sufficiently filter the air. Therefore, if you need a filter to trap pollen, dust mites, and hair, a MERV 8 filter should do its job. But if you have allergies or respiratory problems, choose a Merv 11 air filter or even a Merv 13 air filter.