Guide
How to connect a catio to a window without designing backwards.
Choose the house connection before you commit to the enclosure footprint. A beautiful catio in the wrong relationship to the window is still the wrong catio.
Start with the actual window
Record the window type, clear opening, sill height, trim dimensions, exterior wall material, nearby downspouts or roof edges, and the distance from the opening to the proposed enclosure. Photograph it from both sides.
Decide how the opening closes
Will the catio access remain available all the time? Does the homeowner need to close and lock the house opening independently? Is the connection removable for winter, cleaning, or storm preparation? These decisions affect the insert, pet door, tunnel, and enclosure alignment.
Keep water moving outside
Window openings already have a drainage strategy. A catio connection should not trap water against the sill, interfere with flashing, or create a path for wind-driven rain. Roof runoff from the house or catio also needs somewhere to go.
Do not assume the kit solves the interface
A manufacturer may offer tunnels, window inserts, or enclosure modules. That does not mean the combination automatically fits your specific window or siding. Verify dimensions and support conditions first.
When a wall pet door may be cleaner
A properly planned wall opening can sometimes produce a cleaner permanent connection than adapting an awkward window. But cutting the wall brings different weather, framing, insulation, wiring, and finish questions. It should not be treated as a casual change simply because the pet door itself is inexpensive.