All installation options

Door installation

A new way home.
One step at a time.

Fit OnlyCat into a suitable wood or plastic door. See the whole process, then follow each step at your own pace.

Before you begin

Watch the complete guide

2 min 22 sec · Narrated
An illustrated film showing the ten steps below, from choosing the height to connecting power. Written instructions follow on this page.

Ten illustrated steps. Play, pause and revisit whenever you need.

Jump to a step

Before you begin

A little preparation.

Connect first. Fit second.

Complete app setup and test your OnlyCat and Wi-Fi connection before making permanent changes. Plan the route to a mains socket; a 3 m USB-C cable is included by default.

Connect and test your OnlyCat

Check your door

These steps are for a suitable wood or plastic door. Check for metal, even beneath a plastic surface: a magnet will not detect aluminium.

If metal is present, you may need a larger opening and a mounting adaptor. Ask us before cutting.

Check that the door can open fully without hitting the flap, with a clear, safe route for your cat on both sides.

Have these ready

  • Ruler, pencil and Blu Tack
  • Spirit level
  • Drill, starter-hole bit and 6 mm bit
  • Jigsaw and file
  • Cross-head screwdriver
  • Supplied screws and caps
  • Eye protection

Follow your tools’ safety instructions. If you’re unsure about cutting or fitting, ask a professional installer.

Do not fit into a fire-rated door. Never cut or drill through OnlyCat’s tunnel. It contains the microchip reading antennas; damaging them will prevent the unit from working properly.

Replacing an existing flap? Check the existing opening first. For other surfaces, use the wall or glass guide.

01

Prepare the opening

Set a comfortable height

Ruler and steadying hand beside a white painted timber door while a pencil draws the tummy-height mark.

Measure from your cat’s tummy to the floor. Mark this height on the door for the bottom of the opening.

02

Prepare the opening

Trace the opening

A hand steadies the external frame while the graphite tip follows its inner aperture and reveals the opening outline.

Align the bottom of the frame’s inner opening with the tummy-height mark. Hold the frame with Blu Tack, check it with a spirit level, then trace around its inside edge.

03

Prepare the opening

Drill starter holes

A cordless drill and operating hand approach each of four starter holes square to the door.

Remove the frame. Drill a starter hole at each corner of the outline, large enough for your jigsaw blade.

04

Prepare the opening

Cut and smooth the opening

A hand guides a jigsaw from a starter hole around the opening before the offcut is removed and the edge filed.

Insert the jigsaw blade through a starter hole, then carefully cut just outside the pencil line. Gently file the edges as needed until the tunnel slides in smoothly.

05

Fit your OnlyCat

Check the fit from inside

Two pale hands support full-size OnlyCat as it slides through the opening from indoors.

Guide OnlyCat through the opening from inside. The OnlyCat logo and display face into your home. This is easier with one person inside and one outside.

06

Fit your OnlyCat

Mark the fixing points

The external frame slides on from outside and a pencil marks its two fixing holes.

From outside, slide the external frame over the tunnel. Mark the two screw-hole positions on the door.

07

Fit your OnlyCat

Drill the fixing holes

A cordless drill makes the two fixing holes in the empty door, with OnlyCat and the frame removed.

Remove both the frame and OnlyCat. Drill through the two marks with a 6 mm (¼ inch) bit, keeping the drill straight.

08

Fit your OnlyCat

Choose the screw length

The camera looks directly at the cut door edge. A steel ruler and screw enter the view; aligned guides compare 30 mm of door thickness with a 50 mm screw measured from under the head, leaving 20 mm extra.

Measure the door thickness across the opening, from one face to the other. Choose a screw 15–30 mm longer. Measure the screw from under its head to the tip.

09

Fit your OnlyCat

Fit, secure and cap

A screwdriver and hand tighten the exterior fixings before hands press the two caps into place.

Refit OnlyCat from inside and slide the external frame over the tunnel outside. Tighten the screws from one side to the other without overtightening, then press in the caps.

10

Connect the power

Connect and route the cable

A hand points to the underside USB-C connection; the camera pulls back to show the cable routed towards a switched-off double socket on the wall.

Connect the L-shaped USB-C plug underneath the indoor unit, with the cable facing towards the socket. Secure the cable neatly with clips or trunking. Connect the other end to the power adaptor.

Fitted. Ready for them.

Now make it theirs.

Check the door and flap move freely, with no pulling or pinching of the cable through the full door swing. Once the cable is safely routed, switch on the power.

Head back to app setup to add your cats, choose their house rules and help them get comfortable with their new doorway.

Set up the app and your cats

Based on the OnlyCat OC1000 manual, V2.06.26. Illustrations show a wood-door installation. Full manual & printable template · Safety & care