AllergyZone’s FilterLock was developed to solve a common problem where homeowners and contractors fail to cover the filter slot/door where the 1” air filter is installed. The result is unfiltered air is drawn into the HVAC system and bypasses the air filter instead of passing through the filter. That air also has to be heated or cooled, which drives up energy costs. FilterLock is an inexpensive solution to air leakage at the filter slot. It installs in seconds without any tools. It is a one-size-fits-all product that works with any brand of 1” air filter up to 25” long. Built-in magnets hold it securely in place on metal ductwork.