Building A Plenum With Sheet Metal

A possible construction is all fiberglass duct board with a latitce of metal studs to separate reinforce the top and bottom.

Building a plenum with sheet metal.

Duct board vs metal plenums supply is on perferable over the other. 25 feet should it be ductboard or metal and is hard pipe runs preferable over flex. The two basic methods of tuning an intake manifold are varying the length of the intake runners and the volume of the plenum. But even with all duct board is it still a building cavity.

If i am going to have a supply plenum run for approx. Longer runners improve low and mid range torque at the expense of top. Constructed of 26 gauge sheet metal the knock down design of the plenum takes up very little space and simplifies transporting to the job site. The trim to fit plenum fully assembled measures 20 in.

The sizes of the supply plenums available here fit the furnaces. A supply air plenum is a sheet metal box that attaches to the outlet of a furnace or air handler and is used as a central manifold for other ductwork to connect to. Once the full plenum was welded in the plenum was tossed into the jig. Simply measure and cut to size using tin snips to match the supply opening of the air handler furnace or evaporator coil.

Some lite metal work needed to be done to the plenum in order to mate to the notched sections. Adding the velocity stacks straight to the plenum would be ideal for ease of install at this point but the volume of the plenum even with the stacks in it is still too much. If it s ok with duct board what other materials can make up the walls. Shop for sheet metal duct pipe fittings at ferguson.

Ferguson is the 1 us plumbing supply company and a top distributor of hvac parts waterworks supplies and mro products. Arizona 24 california 24 nevada 23 type plenum 20 plenum drop 4 gauge 26ga 24 lined yes 8 no 13 flange width 0 5 inches 20 1 5 inches 4 width 13 75 inches 6 16 75 inches 6.