Some buildings have incompatible mechanical systems. This stems from both a lack of available products that physically fit in filter housings and increased resistance to airflow, known as “pressure drop.” A MERV 13 filter’s high level of filtration removes more contaminants than traditional media, but also creates more resistance to air moving through it. Because of this, the equipment works harder and uses more energy to move the same volume of air. Some systems can’t provide the added power required to move the minimum airflow needed. Luckily, newly designed MERV 13 filters that cause minimal pressure drop are increasingly available.