Unplug the duet power cord from the outlet. Pull the Whirlpool Duet forward from the wall so you can stand behind the back panel.
Loosen the screw in the clamp around the vent hose where it attaches to the Duet. Pull off the hose.
Remove the bolts on the Duet's back panel along the edges, using a nut driver. Pull off and set aside this metal plate. Now you can see the casing for the heating element on the left-hand side in the cabinet. The metal box mounts vertically on an electrical junction.
Take out the screw holding the lip of the casing onto the junction box. Pull the casing straight up to unplug it from the electrical socket in the Whirlpool Duet.
Remove the screw along the opening at the bottom of the casing to release the heater coils inside. Slide out the coils, which are built into a metal frame.
Slide the new heater coils into the casing and secure the bottom of the casing with the screw. The coils slide into the casing with the connector posts extending from the opening in the casing, at the bottom.
Plug in the casing to the socket in the duet and secure the part with the screw removed in step 4.
Attach the back panel to the Whirlpool Duet using the bolts. Tighten the bolts with the nut driver.
Connect the hose to the pipe on the rear of the Duet and tighten the clamp around the hose.
Plug in the Duet power cord and slide the dryer back into position.