Security window film or security screens: what each one actually stops

The short answer: film holds the glass, a screen holds the opening

Security film keeps a broken pane in one piece for a while. A security screen keeps the opening closed. That's the core difference, and the table below sets out the rest factor by factor.

Film works on the glass you already have, so the window looks the same and nothing changes about how it opens. The glass still breaks, though, and the film's job starts after it does. Laminated glass works the same way but is made into the pane at the factory, with a plastic interlayer between sheets of glass. A security screen is a frame, mesh, lock and fixings fitted over the opening. It has its own compliance label and a set of forced entry tests behind it.

None of the three is a cyclone shutter by default. That point gets its own section further down, because in Far North Queensland it changes the decision more than anything else on this page.

What security film does to a pane of glass: it slows entry and does not stop it

Security film does work, at the job it's made for, which is holding broken glass together. 3M says its Exterior Safety Series helps hold shattered glass together to protect people and property from spontaneous breakage and low-force impacts. Its Ultra Series is described as tear-resistant film that adds protection against smash and grab incidents.

What film doesn't do is keep a determined person out. 3M's own security page says potential intruders will not be fully stopped, and that its Ultra Series combined with its Impact Protection Attachment (IPA) sealant can help delay intruders. Its product caution is blunter: window films are not bulletproof and not designed to stop intruders.

The sealant matters. 3M explains that the IPA sealant anchors the film to the glass frame, and that some of its films require that sealant for break and entry applications. If you're quoted security film, ask whether the frame anchor is part of the job, since the maker ties its break and entry claims to the film and sealant working together.

The downsides of security film for a house

Film's limits for a home come from the manufacturer's own notes, and they're worth reading before you pay for it. 3M lists factors that affect the outcome, including the film chosen, the type and thickness of glass, building construction, the quality of the window or door frames, the intruder's size and strength, and the tools used. Most of those are about your house and the person attacking it, which no film can change.

• The glass still breaks. Film holds the pieces; the noise and the hole start the moment the pane gives way.
• The window has to be shut to be protected. An open sash with film on it leaves the gap wide open.
• Film does nothing for insects or airflow, so you still need a flyscreen on any window you open.
• A weak frame or lock stays weak. 3M names frame quality as a factor in its results.
• Thickness alone tells you little. 3M says safety films should be specified by performance and third-party testing, not film thickness.
• 3M advises talking to security professionals and an authorised film dealer before choosing a film, so ask for the test data on the exact product quoted.

Laminated glass: the interlayer is built into the pane

Laminated glass is the glass maker's version of the same idea. Viridian, an Australian glass maker, describes its VLam laminated glass as two or more sheets of glass bonded together with an interlayer, and says laminated glass is safer when broken because the glass adheres to the laminate.

Security laminates go further with a thicker interlayer. Viridian's IntruderGuard has an interlayer four times thicker than standard laminates. Viridian says it is 20 times harder to break through than standard float glass and withstands repeated blows from heavy objects such as bricks or hammers. It's also a laminated Grade A safety glass.

The catch is the same one film has. Viridian says IntruderGuard should go into window frames and locks of sufficient strength, because a strong pane in a weak frame just moves the weak point. Laminated glass also means replacing the glass, which is glazing work (more on who does that in the FAQ). Like film, it only protects the window while the window is shut.

What a tested security screen does differently

A tested security screen is the only one of the three tested and labelled to the security screen standard. The National Security Screen Association (NSSA) describes a security screen as a physical barrier to entry that allows airflow while keeping insects and intruders out, and says it must pass strict testing to be called one. Its rule for buyers is simple: security doors must be supplied and installed with a compliance label, and if it isn't labelled, it isn't a security door.

The NSSA says screens installed to the installation standard are designed to withstand knife shear, jemmy, probe, corrosion, pull and impact tests. SCREENGUARD, the stainless mesh we make screens with, states its screens pass dynamic impact, knife shear, anti-jemmy, pull and probe testing. The NSSA also says installation is just as important as the door itself and recommends you don't fit one yourself.

For what makes a screen a security screen in more depth, and what the burglary research says about them, see do security screens stop burglars.

Breeze, insects and an open window in Cairns: only the screen covers both

If you like the glass open in a Cairns summer, that's where film and laminated glass stop helping. Both protect a window only while it's closed. Slide the window open for a breeze on a humid night and the protected pane slides out of the way.

That matters because many break-ins need no force. In an Australian Institute of Criminology (AIC) study of 69 self-reported burglars interviewed in Western Australian police custody, two-thirds (66.2%) said they usually got in through unlocked doors or windows, and the rest broke a door or window. Queensland Police say homes with windows or doors left open or unsecured are more likely to attract a burglar. Film and laminated glass only help against the remaining third, and only where the glass was what they broke. A locked security screen covers an open window too.

A screen also keeps mosquitoes out, which glass treatments can't do while the window is open. Woven stainless mesh keeps the view clear. Our perforated aluminium gives about 40 percent view through and suits windows that face the street. If insects are the main worry, our fly screen vs security screen guide covers that side.

Cyclones: none of the three is window protection by default

Don't count on film, laminated glass or an ordinary security screen to protect a window in a cyclone. The Queensland Government's Household Resilience Program explains why the glass matters: if a window breaks, the wind pressure on that wall can enter the house and potentially double the load on the roof structure.

The program funds window protection only when the screens or shutters are installed as permanent external screens covering the full window, with a wind driven debris or wind rating and evidence of compliance such as a valid test certificate. Screens installed inside the window are not eligible. Film sits on the glass itself, so it isn't an external screen or shutter. The program also warns that many screens on the market claim to be cyclone rated but may not have been tested for the wind ratings expected in a category 3 cyclone.

Our guide on security screens and cyclone protection covers what a debris rating means and what to ask a supplier for. Roller shutters are the other common option, compared in security screens vs roller shutters.

Glass doors and sliders: protected shut, exposed open

Film or laminated glass on a slider helps if someone breaks the glass while the door is shut and locked. It does nothing when the door is slid open for the breeze.

A security sliding door fitted in front of the glass door covers both states. With the glass open, the screen door is the barrier. With everything shut, there are two layers to get through. Cairns police have asked residents in the greater Cairns area to keep security screens and doors locked and secured with fitted dead bolts. A screen only does its job when it's locked.

Film and a screen can also go on the same opening: film for the glass, the screen for the gap. Our guide on how to secure a sliding glass door covers locks, bars in the track and the screen door options in order.

Which suits which opening

Choose by what the window needs to do. If it's opened for air, a tested security screen is the only one of the three that protects it open. If it's always shut, a lock to Australian Standards comes first, then film or laminated glass if you want the pane itself harder to get through. Bars are a different trade-off again, covered in window bars vs security screens.

• A bedroom or living room window you open at night: a security screen, so it stays open with insects and intruders out. Queensland Police also ask that grilles and shutters allow an exit in an emergency, so keep bedroom openings easy to open from inside.
• A fixed pane or a window you never open: a window lock first, then film or laminated glass if the glass is the weak point.
• A sliding glass door: a security sliding door in front, with film or laminated glass as an extra layer if you want one.
• A window facing the street or a neighbour: perforated aluminium for privacy, or one way vision mesh over a grille.
• Cyclone protection: a product with a debris or wind rating and test evidence, whatever else you choose.
• Glass that breaks on its own or a safety glazing upgrade: film or laminated glass, which is what those products are made for.