Cat Window Box Guide: Everything You Need to Know

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cat window box
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A cat window box is a great way to give your beloved pet somewhere to relax that’s not in the way. Plus, if you live in a city or in an upper-floor apartment, it saves you worrying about letting them out.

In this guide, we’ll go over everything you need to know about choosing a cat window box for your apartment or condo.

What is a Cat Window Box?

A cat window box (also known as a cat solarium or window catio) is a box that fits into your window frame. It can be open with railings or completely enclosed and is designed to give your cat somewhere to sleep in the sun.

Essentially, they fit into the window frame almost like an AC unit: you slide the window up, slot the box in, and then shut the window slightly to hold it in place.

Why Get a Cat Window Box?

An outdoor cat window box gives your pet somewhere to sit that’s outside, rather than just sitting by a window. Most cats do this anyway because they love the sun, so they might as well get some fresh air, too.

It’s also a good way to keep them safe if you live above the first floor. That said, they’re useful for first-floor apartments and condos if you live on a busy road.

In short, a cat window box is a good halfway point between the indoors and outdoors.

Considerations Before Buying an Outdoor Cat Window Box

There’s not a ton to think about before buying a window catio, but bear in mind the following:


Unless you’re making a DIY cat window box, you’ll need to make sure it fits your window. This shouldn’t be too difficult; just measure your window frame before you go shopping.

Equally, the box should give your cat enough room to stand up and stretch out. If you have a balcony, you have a bit more freedom with size because you can support the box using posts.


This’ll only really apply to first-floor apartments and condos. Fitting a cat box into your window may compromise balcony security if it’s not screwed to the window. But this isn’t a massive concern, as you can always remove it when you’re out or asleep.

Building Restrictions

If you’re allowed to have a cat in your home, there’s probably no issue with having a cat window box. Always check your regulations first. The main problem might be security, as mentioned above.

Types of Outdoor Cat Window Box

There’s not much difference between the types of cat window box you can buy. Even so, here’s a quick roundup of what’s available so you can choose the right one.

1. Indoor Window Shelf

While technically not a window box, cat shelves can come as boxes. These basically give your cat somewhere to sleep that isn’t the windowsill, which should hopefully stop them knocking your decorations over!

Most stick to the window using suction cups, although some hook onto the window frame instead. The latter option is better for chubby cats, as suction cups can’t hold a ton of weight.


  • Widely available
  • Keeps your cat indoors
  • Inexpensive


  • Can’t support loads of weight
  • Doesn’t give them a chance to go outside

2. Flatpack Kit

Some companies make flatpack cat window boxes. All you need to do is buy and then assemble. As such, they’re a convenient option if you want something large and secure.

For example, this cat window box is plexiglass with a shelf. Others might be wire or mesh instead.

Although easy to assemble, the biggest drawback is that they come in standard sizes. So, while these might work for some, they won’t work if you have odd-size windows. This might be the case in older buildings or apartments with French doors.


  • Easy to assemble
  • Convenient alternative to DIY options
  • Fairly secure


  • Expensive
  • Come in standard sizes

3. DIY Screen or Mesh

A common option for a cat window box is to make your own using wire or mesh. Stretched over a wood frame, it’s a good option for providing light and a breeze while still keeping things secure. Alternatively, you could use chicken wire or fabric mesh.

All you’ll need to get started is some lumber, wire and screws. You can find some great plans here.

To build one, do the following:

  1. Measure your window and ensure the box is wider by a few inches. If you have a window that opens up, the box’s height should be level with the open window.
  2. Start with the floor, which can be MDF. Measure and cut it so size.
  3. Cut the vertical and horizontal supports from 2×4. There should be one for each corner and one for each side of the roof (so 8 in total).
  4. Fix these in place using glue and nails for security.
  5. Line everything with wire, stapling in place.
  6. On the floor, lay some rubber mat or something easy to clean.
  7. Cut some vertical supports for anchoring the box to the building.
  8. Fix the box to the building using vertical and horizontal supports.
  9. If you feel like it, install a cat flap in the window for convenience.

You can check out this video for more visual instructions.


  • Fairly easy to build
  • Customizable to your window size
  • Mesh provides security while still being open


  • Fabric mesh tears easily
  • Does require tools and materials to build
glass cat window box

4. Plexiglass

Plexiglass is a popular option because it’s sturdy and provides a completely clear view of outside. You can buy a cat window box with plexiglass (such as the one above) or make your own.

However, plexiglass sheets can be difficult to work with, as you need specific drill bits that prevent them from cracking. Also, the material is durable but can scratch easily, making it look unattractive. And, considering cats are scratch machines, this’ll happen fairly quickly.


  • Durable
  • Gives a clear view
  • More secure than mesh


  • Can scratch easily
  • Plexiglass is difficult to work with

5. Railings

Rather than mesh or plexiglass, you might find an outside cat window box with railings. While it might look a bit like a jail cell, it’s a good option if you trust your cat not to try to escape.

These models are usually curved with plexiglass on the top and bottom and then railings along the side. They offer good air circulation, which is great in warmer climates.


  • Offer the most freedom
  • Look more decorative than other kinds


  • More difficult to build/less common to buy
  • Not suitable for colder areas

Final Thoughts

By now, you should have a better idea of a suitable cat window box for your condo or apartment. Making a DIY cat window box is a great idea if you have the tools and time. Not only can it be cheaper, but you can make it to your exact size needs.