Air Furnace Filter Alarm Whistle for Heating & Air

Know when to change your filter, know when to start saving. Our Air Filter Whistle lets you know when it's time to change your heating and air conditioning filter. If you change your air filter regularly, you reduce the risk of breathing unhealthy air and prevent your heating and cooling system from running harder than necessary. In addition to reducing your energy costs, changing the filters can extend the life of your heating and cooling units and keep them operating properly. The Furnace filter alarm whistle includes - 2 parts - the base and the hat - (image shows both sides). As dirt builds up, it produces an increase in pressure, which triggers the whistle.