You will no longer worry about cold spots in your home when you make this filter your first choice. This standard grade furnace filter is made with a filtering medium of continuous strand spun fiberglass. You can be confident knowing its heavy duty build helps to alleviate unnecessary strain on your furnace equipment, and maximum airflow will evenly distribute both heat and cool when you need it. Each new filter installation delivers 30 and 90 days of reliable performance. Enjoy trouble-free air conditioning and central heating by replacing your furnace filters regularly with a Duststop air filter today.