The filters which are composed of materials that are folded into pleats so as to maintain a good air flow within the HVAC systems are called pleated air filters. Such air filters are more efficient than conventional fiberglass filters and are also less expensive than electrostatic filters. The pleated filters meet all the prerequisites of standard air handling systems such as frame dimensions, depth, and performance filters. Some filters which are made up of plastic and have no metal parts thus eradicate the risk of corrosion and puncture and can be incinerated completely.