Cat Door for Up & Down Windows
If your window is a single-hung or double-hung sash — the kind that slides up and down rather than side to side — you can add a cat door without cutting a hole in your wall, door, or the window itself. The insert fits into the opening created when you raise the lower sash and adjusts to your window's width.
$90
What counts as an "up and down" window?
Single-hung windows (where only the bottom sash moves) and double-hung windows (where both the top and bottom sashes move) are both up-and-down windows — the classic style found in most homes, where you raise the lower sash to open it. This insert is built for that style: it fits into the horizontal opening created under the raised sash.
How installation works
This insert is width-adjustable from 16 to 36 inches to match your window's width, with no drilling, adhesive, or permanent hardware. The top edge is padded with a flexible TPU strip for a secure seal against the sash above it. Watch the full process below:
What you get
- Cat passage opening: 7 inches wide by 7¾ inches tall
- Swinging door flap with a 4x4 inch clear acrylic window
- Two-way sliding locks to hold the flap shut in or out; magnet holds it in place when unlocked
- 3D printed in PLA+ plastic with a flexible TPU seal strip
- Patented design
Frequently Asked Questions
Does this work with double-hung windows, where both sashes move?
Yes — the insert only needs the lower sash raised to create the opening it sits in. Whether your upper sash also moves doesn't affect installation.
My window is wider than 36 inches — is there anything I can do?
Yes. 8-inch extension panels are sold separately in sets of one, two, or three to extend the width range beyond 36 inches.
Does it work with casement or crank-style windows?
No — this insert is built for single-hung/double-hung sash windows, not crank-out casement windows. If your window slides side to side instead, see the sliding window page.
Do I need any tools to install it?
No. It's designed to be tool-free — no drilling, screws, or adhesive.