What are Sliding Windows and Are They Safe?

By thewriteDuffy •  Updated: 04/08/24 •  9 min read

When closed, most windows look about the same, so it can be a little difficult to know the differences between them.

So, what exactly is a sliding window? Sliding windows have moveable panels, that slide left and right. This is different from other types, like casement windows that crank to open out, or awning windows that open by pushing out.

What Is a Sliding Window Called?

You’ll find sliding windows referred to as slider, glider, or “horizontally sliding windows.” Essentially, you can use this term to describe any windows that slide open and shut horizontally.

With that said, sliding windows clearly take their name from their opening mechanism, so it’s common to hear people call a window that slides up and down to open a sliding window as well, but these are actually a whole different type of window.

Sash-hung Window vs. Slider Window

Slider windows are often mistaken for hung windows, which look a bit more threatening. As I briefly mentioned above, windows that open by sliding up and down are often called sliding windows, but these are actually sash-hung windows (also called sash windows; or single-hung windows and double-hung windows, which references how many of their sashes open and close).

It can be a little confusing with all these names, but in short, if it slides open horizontally it’s a slider window, if it slides up or down to open, it’s a hung window.

Though sash-hung windows can sometimes stop staying open and the top window will slide down, the chances of this happening after you’ve already opened it are slim. A hung window may start not staying open when the balance shoes inside it aren’t working properly, and that wouldn’t spontaneously happen without damage being inflicted.

What Are the Different Types of Sliding Windows?  

There are three main categories of sliding windows: the single-slider, the double-slider, and the three pane-slider. The three variations differ in the number of panes they feature, but each have at least one slidable pane. The variety of sliding windows means there’s a style to suit most homes, aesthetics, and ventilation needs.

Single-slider Windows

Single-slider windows have two panes – one fixed and one moveable.  This gives a lovely simple look, but only allows for opening on one side of the window.

Double-slider Windows

Double-slider windows have either two or three panes and differ from single sliders in that two panes are moveable.  This allows for greater versatility of ventilation in a room and the multiple panes can suit larger rooms.

Three-pane Slider Windows

Three-pane sliders differ from the three-paned double sliders in that they generally have a larger, central picture window which is flanked by slider windows. Despite the multiple panels, this style still has a very simple, minimalistic appearance and due to their opening mechanism, they’re super easy to operate.  This also helps if you’d like to place a generous window in a hard-to-reach spot such as a hallway. As long as you can reach the bottom of the window, you can easily open and close the panels.

Are Sliding Windows Safe?

Though the idea of being able to easily slide a window open may seem like a cause for concern, sliding windows are actually one of the most secure types of windows.

Slider windows have a straightforward design that doesn’t require a lot of complicated parts and pieces, This means they close, seal and lock much easier than other window types.

Even better, if you’re truly worried about break-ins sliding windows allow you to do the age-old stick trick.

By simply placing a stick into the window frame on the side that stays closed, it becomes impossible to open the window from the outside.

Do Sliding Windows Have Screens?

Screens can help enhance security and keep insects and debris out of your home so you may be concerned about whether they come with slider windows or not.

Thankfully, many slider windows come with screens or can easily have screens fitted to them.  With that said, a sliding window will work perfectly well without a screen and it really just comes down to personal preference.

Are Sliding Windows Cheaper?

One of the benefits of sliding windows is their affordability.  Cheaper than other window styles of similar proportions, the sliding window lacks the more complex mechanisms of the likes of tilt and turn or double-hung windows. This makes them a great option if larger windows, such as a picture, would suit your room but not your budget.

The runner used to open and close slider windows cost less than the operational systems found in other styles and their accessories tend to be pretty simple (and therefore inexpensive) too. What’s more, fitting costs tend to be lower because installing a sliding window is relatively straightforward – and therefore fast, cutting down on the hours of labor.

This all sounds great, right?  But there are a few things to keep in mind. Though the initial outlay may be lower, there are sometimes maintenance costs involved in sliding windows. Due to the track inside the frame, there isn’t such an airtight seal and this can translate to leaks and dust entrapment.  If your sliding window is poorly maintained, it will become less energy-efficient, leading to heat loss from the interior and cold air entry from the exterior, especially during high winds.

Which Direction Should Sliding Windows Open?

As we now know, slider windows open from side to side, moving on their runner within the frame. A sliding window can be referred to as left-handed or right-handed and you must remember that it is taken from the viewpoint of someone standing outside your home. Typically, slider windows are left-handed.

Different types of openings for sliding windows are identified using X and O. “X” is used to identify the sliding part and “O” the fixed part.  An X-O window has the sliding part on the left and the fixed part on the right (as viewed from the outside) and this is by far the most common style. You can get slider windows that open up and down, for installing vertically but make sure that you’re purchasing a vertical model, not a horizontal one.

If you’d like to change the “handedness” of an existing slider window, with many models you can do so.  If the stable panel is on the same track as the slider panel, a builder can usually easily make the switch for you without removing the entire window system. If the stable panel isn’t on the same track, unfortunately, it’s a more complex job to alter.

Are Sliding Windows Any Good?

Sliding windows are wonderfully easy to use, have a pleasing aesthetic and modern models, when well-maintained, are durable and offer better energy efficiency than some other window styles.  When it comes to getting a large window to allow in plenty of natural light, they’re also a money-saving option.

Best Spaces for Sliding Windows

Sliding windows are often best for wide spaces, to give you an expansive view and allow them to open easily. If placed in a tall and skinny space, a sliding window would be more difficult to open.

Slider windows, especially wide ones, offer superb ventilation, making them good for rooms that become uncomfortably stuffy on sunny days. On the other hand, if you have a dark room that can feel a bit cold and gloomy, slider windows allow plenty of warming, illuminating light in.

As far as their aesthetic, slider windows fit well in colonial, ranch and mid-century homes, but modern and art deco properties can also suit this style.  Slider windows have slim, sleek lines, which can work well with a range of interior decor styles, being elegant and minimalistic.

Love to load your internal window sills with pretty possessions or external sills with pots of plants? The sliding window is ideal as there are no swinging frames to contend with.

The downside?  Unlike inward opening windows that facilitate cleaning from the inside, you’ll need to hop on a ladder to clean the exterior of slider windows on upper floors.


The range of sliding window styles is much bigger today than it has been previously, with options to suit nearly every home. Slider windows are attractive, they allow plenty of light into a room, are reasonably priced and we must salute them for the number of problems they serve as a practical solution for! If you’re still not sure if a sliding window is right for your space, click here to see our list of the 13 most popular window styles for your home.

Modern sliding windows are pretty good in terms of energy efficiency thanks to advancements in double glazing.   Problems generally only occur within the warranty as a result of poor fitting and lack of maintenance, but when these problems do occur, repairs can be costly. They’re a particularly good call for anyone who struggles with their strength or mobility, being easy to operate.  For this reason, they’re often found in homes for the elderly or supported living properties. 

Stunning as the likes of picture, bay, and bow windows are when you’re trying to flood a space with pleasing natural light, the cost of this vision can be prohibitive.  Sliding windows are a cheaper alternative to creating this look and their accessories and handles can be modified to suit your overall aesthetic.  Likewise, they offer a budget-friendly way to bring light into cellars or dark hallways where other styles are proving too expensive.


At home, April is a mom, wife, and DIY darling. Among other home projects, she helped her husband Dan renovate their 1986 bungalow and is currently designing and decorating the 2023 custom home they are building themselves. Professionally, April is a writer, author, and online marketer with 15 years of experience writing for newspapers and magazines, building online authority websites, and publishing books.