Window catios

A window catio is a mesh box that sits in a window opening, sometimes on its own and sometimes as the doorway to a tunnel running out to a larger enclosure. It is the smallest and cheapest way into this category, the only one most renters can install, and for a single indoor cat in a flat it is frequently the whole answer rather than a step towards a bigger one.

Prices and specifications checked 12 September 2026

One seller, one product

This is the finding that shapes the page. Of the 68 Australian products we could source, 1 is a window box, and it is Omlet's. Somerzby, Catnets, Coops and Cages, Betta Pet Systems, My Chicken Coop, Samland, Kmart and the Bunnings marketplace sellers publish nothing that mounts in a window. That is not a ranking. It means the Australian window catio market, as published, is one product with one price list, and everything else on this page is a workaround built from other parts.

Omlet publishes the whole tunnel system as a price list, which is more transparency than the rest of the category offers on anything:

Read that list in the order you would actually buy it. The window box is $100, but it cannot be fitted to a window without the window board at $109, so the real cost of putting a hole in the wall of the house is $209, and the board is the dearer half. One straight tunnel section adds $90, which puts a window opening plus a short run at $299. A tower at $120 is what takes the tunnel down from a first-floor window to ground level, and it is the part people forget when they are pricing a flat.

What fits a standard window

Nothing published answers this, and the gap is worth naming rather than filling with a guess. Omlet publishes a dimension diagram for the tunnel system, but it carries five sets of labelled figures without saying which set belongs to which component, so we recorded no dimensions at all for the window box rather than attributing the wrong ones to it. No seller in the category publishes a minimum or maximum window opening, a sash travel, or a list of window types the board suits.

Australian windows do not help either, because there is no single standard. A sliding aluminium window, a double hung timber sash, an awning window that opens outward and a louvre all present a different opening, and two of those four cannot be left partly open with a box in them at all. The practical sequence:

1. Measure the clear opening, width and height, with the window open as far as it goes.
2. Check what holds the window at that position. An awning or casement window held only by a friction stay is not a fixing point for anything.
3. Ask the seller in writing whether the board suits that opening and how it is held. Keep the answer. It is the only specification that exists for this product.

Does anything get screwed into the frame

We cannot tell you, and we are not going to imply we can. The board is the component that does the fitting and no published page states its fixing method, its fasteners or whether it clamps, tensions or screws. That is an unresolved question rather than a reassuring answer, and it happens to be the exact question a renter needs settled before ordering.

The line that matters to a landlord is not really about screws, though. It is whether the installation changes the building. A unit standing on the floor is furniture and you take it with you. A board fastened into a window frame, a sill or a wall is an alteration to the property, which in most residential leases needs written consent and usually a commitment to make good on the way out. Tenancy rules differ by state and leases differ from each other, so the useful move is to ask in writing, keep the reply, and treat a refusal as a reason to choose the freestanding option rather than an argument to have.

A reasonable landlord objection is a specific one: damage to the frame, a hole in an external wall, water getting in behind a fitting, or a structure hanging off the building. A freestanding mesh unit sitting on the floor inside, or on a balcony slab, gives them very little to object to.

The no-fixing alternative

If the answer has to be "nothing touches the building", the substitute for a window box is a small unit that stands on its own beside an open window, with the window itself screened. It is not as good: the cat does not come and go on its own unless you leave the unit open to the window somehow. It is also cheap, reversible and portable, and it is what most renters actually end up with.

These are the smallest units we could source, all of which stand on the floor and fix to nothing. Floor area is computed by us from each seller's published dimensions, because no seller in this category publishes a floor area, for any of the 68 records we collected:

Two of those deserve a sentence each. Somerzby's Condo has the tightest mesh aperture anywhere in our data at 10 by 10 millimetres, and Somerzby positions it for patios, balconies and undercover areas, which is the window-adjacent use exactly. Catnets' Lite Tower is the tallest thing on the list and Catnets itself warns that it can tip, and says to stand it against a wall or peg it down on hard surfaces. On a timber floor next to a window there is nothing to peg into, so the wall is the answer.

Mesh size, and kittens

A window box is mesh like anything else, and the aperture is the one safety-relevant number in this category. Omlet publishes its catio mesh in two parts, in millimetres: lower half 25 x 75, upper half 50 x 75. Omlet's own guidance is that because of that aperture a kitten or a very small cat may need extra mesh or covers added to the upper half. Catnets says kittens of six months and under should not be left unattended in its netted enclosures for the same reason.

Those are two of very few sellers that say anything at all. Nobody in this category publishes a wind rating either: 0 of 68 products. For a window box, low to the ground and against a wall, wind matters less than it does for a freestanding run, which is one of the few genuine advantages of starting here.

When this is simply the right answer

This is the softest sale on the site, and it should be. One indoor cat in a flat, with a window that catches afternoon sun, does not need a $1,999 walk-in run in a yard it does not have. A window box gives it outside air, a place to sit in the sun and something to watch, which is most of what an enclosure is for.

It is also fair to say that some readers need nothing. A cat that has never been outdoors, is not scratching at the door and has enough vertical space indoors is not being deprived by the absence of a mesh box. If your council requires containment, the obligation is to keep the cat on the property, not to buy a particular product: that is set out in the council register.

If a window box turns out to be too small, the next steps are a tunnel to a run, which is priced in runs and tunnels, or a full attached structure, which is priced in catios. If the outdoor space you have is a balcony, start at balcony cat enclosures instead, because the constraints there are drilling and approvals rather than price. And if you have an existing verandah or courtyard to enclose, netting it is cheaper per square metre than any framed unit on this page: see cat netting.

Common questions

What does a window catio cost in Australia?

The only window product published with a price in our data is Omlet's window box at $100, and it needs the separate window board at $109 to fit to a window at all, so the real entry cost is $209 before anything is connected to it. Add one tunnel section at $90 and you are at $299. That is still the cheapest way into this category by a wide margin: the cheapest freestanding unit we could source with a computable floor area is $260.

Will a window catio fit my window?

Nothing published will tell you. Omlet's own tunnel diagram carries five sets of labelled figures but does not say which set belongs to which component, so we recorded no dimensions for the window box rather than guessing, and no seller in this category publishes a minimum or maximum window opening. The check is yours: measure the opening width and height, and the sash travel if it is a double hung, and ask the seller in writing whether it fits before you order.

Does a window catio have to be screwed into the window frame?

The board is the part that does the fitting, and no seller publishes its fixing method, its fastener list or whether it is tensioned or screwed. Treat that as unresolved rather than as a yes or a no, and ask before ordering if it matters to you. If you cannot risk a fastener anywhere, the reliable answer is a freestanding unit placed at an open window instead, which fixes to nothing.

Can a landlord refuse a window catio?

They can refuse an alteration to the property, and whether your installation is one turns on whether anything is fastened to the frame, sill or wall. A freestanding unit standing on the floor is furniture. A board screwed into a window frame is a change to the building fabric, and most leases require written consent for that plus making good at the end. Residential tenancy rules differ by state and leases differ from each other, so ask in writing, keep the reply, and price the "make good" into the decision.