How to Recirculate Hot Air Into an Intake Vent

Choose the place in a room where you want to place your return air vent. Select an unobtrusive spot near the floor.

Use an electric saw to cut a hole in the drywall matching the size of the vent grill you have chosen. Reach through the hole and use the saw to cut through the flooring to make a hole leading to the basement. Cover the hole with the screw-on grill.

Cut similar holes in the other rooms you want to vent to the basement.

Go to the basement and find the first hole you cut. Begin installing return air panning, using a hammer and nails to connect it to the joists. It should run toward the heater. Repeat this step with all the other holes. The ends of the return air panning should all meet near the furnace.

Cover each of the holes with the rectangular air duct covers and nail them into place. Use duct cutters to cut holes in the bottom of the air duct covers to fit the panning.

Measure the unhemmed edge of the ductwork and cut S-slips to 1/2 inch less than this. Begin installing your ductwork, hammering it into place using metal hanging straps connected to the joists.

Slide the S-slips onto the unhemmed edges and slide in the drive cleats as you go. The ductwork should run to all of the holes in the panning.

Cut holes in the duct section bottoms where they meet at the furnace. Turn off your furnace if it is on.

Connect a single duct to each of the holes you just cut. Run the duct down to the side of the furnace.

Use a saw to cut a hole in the side of the furnace. The measurements should be the same as the filter rack you selected. Connect the filter rack to the end of the ductwork.

Connect the filter rack to the hole you made in the furnace and insert a filter. Seal all the ductwork with caulking.