A temporary debris trap and air filter which may be installed on floor vent openings in the early stages of home or commercial construction. After the floors are cut open for vent openings, the trap and filter is laid over the opening and easily affixed by adhesive strips on the flanges. The screen on top prevents construction debris from entering the duct boots and duct system and the filter below prevents dust and fine particles from entering the system while simultaneously allowing the free flow of cooled or heated air to enter the room area. The air will not be obstructed so the building and construction materials can be acclimatized during the construction period, the HVAC system can be tested and adjusted for proper air balance and the construction workers can breath filtered and conditioned air.