Endura Flap Thermo Sash 3e Pet Doors For Sash Windows - Installation Instructions

Installation Instructions

sash window pet door diagram


  • 1x Sash Window Pet Door
  • 1x Foam Weather Strip
  • 1x Center Post Weather Seal Draft Stopper


Step 1: Loosen the thumbscrews at the end of the sash. This allows the spring mechanism to move freely from side to side.

Step 2: Insert the sash into the window track. Push against the spring mechanism and swing the opposite end into the opposite window track. Gently release. Tighten the thumbscrews. If the pet door sits properly, remove the pet door to put on the foam weather-stripping in step 3.

inserting the sash into the window track

Step 3: Apply the foam weather-stripping by peeling back the paper and exposing the adhesive. Unroll it along the edge of the sash, pressing to ensure it adheres. Install on both the top and the bottom. Trim to fit with scissors.

applying the foam weather stripping

Step 4: Mount the Center Post Weather Seal Draft Stopper. This strip prevents air from leaking between the window frame when raised to accommodate the sash. Trim to fit with scissors.

mounting center post weather seal draft stopper


permanent lock option

For a permanent lock, install a wood screw in the track immediately above the window on both sides. You will no longer be able to raise the window. For a temporary lock, place a removable wooden dowel or Charley bar in either track above the window, shown in Detail 1.

switching the side of the flap


Remove the screws on the top and bottom closest to the edge of the pet door. Then slightly loosen the screws closest to the glass. Next, slide off the side piece, then the flap assembly.

removing a pet door flap

Rotate the flap assembly (essentially flipping it upside down) then slide it back in. Make sure the locking cover is on the same side as the thumbscrews. Replace the end spacer and screws.

setting flap back in


Make sure you place steps or ramps leading to your pet’s door at a height that works! When they go through the flap, the top of the flap should be at least 1" (2,5 cm) higher than the top of their back. Watch your pet and adjust as needed to keep them comfortable.

adjusting window hight for sash pet door