Using your K&N HVAC filter is easy. First, measure your HVAC system to ensure the 24 x 30 x 1 filter fits. Then, remove the old filter and slide the K&N filter into place. For maintenance, when the filter looks dirty, take it out. Wash it gently with mild soap and water. Let it dry completely before reinstalling. Avoid using harsh chemicals or scrubbing too hard as this can damage the filter. Check the filter regularly, about once a month, to see if it needs cleaning. With proper care, your K&N filter will last for the life of your HVAC unit.