Last Updated on March 4, 2022 by Alarm New England

Most burglars enter through doors. About 65% of them break in through either the front door, back door, or garage.

The second favorite way for a burglar to enter is by climbing or breaking through your windows, especially those on the ground floor.

That’s why knowing how to protect your windows is essential to making your home safe.

Types of Windows and How to Secure Them


Double-Hung Windows

Double-hung windows, often found on older homes, tend to be most vulnerable to break-ins.

A double-hung window has two panes of glass, one above the other, and are often secured with a crescent latch.

Window Alarms

The latch is generally not designed to be extremely secure; it just keeps the window closed. The problem is that the crescent latch is easily jimmied open by inserting a knife or other flat tool.

Another problem can occur when the windows swell due to hot weather because the crescent latch might not close properly. In older homes, it’s common to see that the latches have been painted over so many times that they can no longer effectively secure the window.

But there is a solution.

Drilling and “pinning” is an inexpensive and effective way to secure double-hung windows. To pin your double-hung windows, you’ll need a drill and some nails, rods, bolts or other pinning material.

All ground floor windows should be pinned. The exception would be if there are small children in the home. In that case, one window should be designated for fire emergency exit, and not pinned.

Casement Windows

There are basically two types of casement windows:

window security

Type A: hinged on the side, and cranks or swings outward

Casement windows

Type B: hinged at the top and swings outward

If you’ve got a Type A window, it may be possible for a burglar to break out the window in the area of the crank, reach in and crank open the window. Or if the window is partially open, he may be able to cut or remove the screen and again reach in and crank the window open far enough to get in.

You’ll want to inspect your window hardware. If your push bar or operator is worn out, it should be replaced. It should be sturdy enough that, if your window is cranked open a few inches, a burglar won’t be able to simply force the window open to gain entry –at least not without breaking the window or the window frame.

Statistically few burglars force open casement windows if it means breaking the glass.

Why? Because burglars hate making loud noises. Breaking windows will alert the whole neighborhood to their presence.

Securing casement windows is difficult, especially thin gauge aluminum casement windows commonly found on cheaply constructed homes and apartments. To secure these windows, you may have to replace them.

Jalousie (Louvered) Windows

This type of window is often found in bathrooms or kitchens on older homes. The vulnerability with this type of window is that the individual panes can be easily broken or, in some cases, simply removed by sliding them out of the frame. The panels can also be forced open easily.

Jalousie Window

To prevent someone from removing the panes of glass, you can glue them in. That’s not going to stop someone from breaking them however. If ventilation is not critical, you can bolster security by putting up a storm window, or replacing it with a double-hung window.

Additional Ways to Secure Your Windows


Bars, Grates, Wire Mesh

You can add security to any window by putting up security bars, grates or wire mesh.

Caution note: Before you put up bars, grates or wire mesh over your windows consult your fire code! Putting bars, grates, or wire mesh may cause a serious, life threatening situation in the event of a fire.

While we’re on the subject of bars and grates, there is the question of whether to put them on the inside or the outside.

barred windows

Putting bars on the outside where they are more visible can act as a deterrent to the burglar and discourage them from attempting to break-in.

If you are going to protect your windows with bars or grates, many recommend putting them on the inside. While they might not be as visible to the burglar, and he might break a window before he figures out you’ve got bars, it will likely deter him. A broken window is a small price to pay to keep burglars out.

If you are installing bars, they should be installed in such a way that with one simple motion, like pushing a quick-release lever, the whole assembly falls out or swings out of the way, allowing you to easily escape during a fire.

Hinged Home Security Bars

This quick-release mechanism should be far enough away from the window so a burglar wouldn’t be able to break the glass, and reach in to activate the release to gain entry.

Below are some guidelines to help you determine whether or not the bars you have or are planning to install are will provide you with a safe method of escape in case of an emergency.

Unsafe Bars:

– Can not be opened
– Require:

  • A key
  • Special knowledge
  • A separate tool
  • Extra physical effort

Safer Bars:

– Can be easily opened from the inside
– Have approved quick release mechanisms

When burglar bars are installed on exit doors or windows of sleeping rooms they must be equipped with an approved quick release device which allows them to be opened from the inside without the use of a key, separate tool or any special knowledge or effort.

Note: There may be laws requiring quick release devices to be approved in writing by your local building or fire officials.

There may also be laws requiring your home to be equipped with an approved smoke detector if burglar bars are installed.

Glass for Security and Safety

Another problem homeowners often face when protecting their windows is how to let light and ventilation into a room while keeping burglars out.

The most cost-effective method of making your windows tougher to defeat is by using window film such as BDF S8MC Window Film. Adding an additional layer on your windows helps make them more resistant to impacts, further delaying the burglar.

A more long-term but expensive solution is to install panes of glass specifically designed for security and safety purposes.

Tempered Glass

Ordinary glass can be shattered relatively easily on contact. Tempered glass is treated to resist breakage and so can be utilized for both safety and security purposes. It is not as tough, however, as some other types of glass discussed below.

Thermally tempered Glass

Thermally-tempered glass is made by placing a piece of regular glass in an oven, bringing it almost to the melting point and then chilling it rapidly. When shattered, the glass breaks into relatively harmless chunks resembling rock salt, free of sharp edges.

comparison between annealed, tempered and laminated glass

Fully tempered glass is three to five times stronger than glass that has not been tempered and is five times as resistant to heat. Once the glass has been tempered, it cannot be cut or processed further. Tempered glass can be any thickness, and almost any type or color glass may be tempered except wired glass or glass with a deep patterned surface.

Tempered glass is a logical choice for installation along passageways, in entrance doors and adjacent panels. Building codes in many jurisdictions now require this type of glass in areas or locations where individuals are likely to bump into it.

Laminated Glass

Laminated glass is well-suited for installation in street-level windows or displays, doorways, and other access areas where security is necessary. It is composed of two sheets of ordinary glass bonded to an intervening layer or layers of resilient plastic material, typically PVB (polyvinylbutyral).

structure of laminated glass

When laminated glass is broken, it may crack and break, but the pieces of glass tend to adhere to the plastic material. If a hole is produced, the edges are likely to be jagged, as with ordinary glass.

Laminated glass helps protect against the “smash and grab” criminal. A criminal who encounters this type of glass cannot simply hammer his way through it within a few seconds and will be inclined to move to an easier target. However, given enough time, a burglar will be able to defeat laminated glass.

Bullet-Resistant Glass

For extreme situations where you need serious protection, you can install bullet-resistant glass. However, the cost is high as this is one of the most expensive window protective measures available.

bullet resistant glass

Bullet-resistant glass is laminated, consisting of multiple plies of glass and plastic stacked up to a variety of thicknesses, from 3/4 inch to 3 inches. The thicker the glass, the more protection. The various thicknesses can be certified under Underwriters Laboratories, Inc. specifications for indoor and outdoor installations.


Plastic glazing material can be divided into two general categories – acrylic and polycarbonate. Both are available in a variety of patterns and in a wide range of transparent, translucent, and opaque tints, as well as in clear form. Acrylic is more transparent than polycarbonate, while polycarbonate possesses outstanding strength against impact.

Due to the way acrylic and polycarbonate expand and contract in changing temperatures, both must be installed by a professional. Both are prone to scratching, so exercise extreme care when cleaning these surfaces.


A sheet of acrylic material (Plexiglas) is less than 50% as heavy as glass, about 43% as heavy as aluminum. A one-square-foot, 1/8-inch-thick sheet weighs about 3/4 of a pound. It is available in varying thicknesses and it has much more impact resistance than double-strength window glass.

For example, in thicknesses from 1/8 inch to 1/4 inch sheets, it is 17 times more resistant to breakage than comparable window or plate glass and so it is an approved safety glazing material.

It is not only safer than glass due to its breakage resistance but, when it is broken, it does not shatter into small slivers with sharp edges, but breaks into comparatively large, dull-edged pieces.


Polycarbonate is almost unbreakable. It has 300 times the impact resistance of glass and 20 to 30 times the impact strength of acrylic. It is expensive — about four times the price of standard glass. But if your property is repeatedly being vandalized or broken into, it may well be worth the additional cost.

Polycarbonate is an ideal choice for small windows like those found in doors. Storefronts that are frequent targets of “smash and grab” burglaries may also be good candidates for this type of protection.

Polycarbonate should be professionally installed. If you hit it with a sledge hammer it probably won’t break, but if it’s not installed properly, the whole window is likely to get knocked right out of the window frame.

Polycarbonate sheets, like acrylic sheets, weigh 50% to 60% less than glass. It has a slight blue or gray tint, and so it is less clear than other types of glazing and shows some distortion. This type of material is reported to be less weather resistant than glass or acrylic, but can be expected to remain serviceable and attractive for seven years or more in outside installations.

For burglary-resisting applications, a 1/8-inch thick polycarbonate sheet meets the Underwriters Laboratories Standard 972, “Burglary-Resisting Glazing Material.” A laminated polycarbonate sheet one inch thick (nominal) meets UL standard, U.L. 752, “Bullet-Resisting Equipment”, for medium power weapons.

Check your local fire code before installing polycarbonate in your bedroom windows to be sure you are not in violation.

Secure Your Windows with a Home Security System


While there are many steps you can take to reinforce your windows and keep them well-protected from intruders, the methods above are primarily delay tactics to buy time for police to arrive. The best way to get help from the police when you’re in trouble is to self-install a home security alarm system in your residence or find a security system company to install and monitor it 24/7.

Self-installed home security is great when you’re on a budget but you or a family member has a few spare minutes during the day to get it set up. Alternatively, you can opt for a professional installation if you have a complex system with many components which will take longer to install. Contact a reputable alarm company for more information on what kind of security system is most suitable for your home and lifestyle.

To learn more about home security, check out our Ultimate Guide to Home Security.