Best Window Locks and Security Bars to Stop Intruders

Windows are the second most common entry point for burglars, right behind front doors. Standard factory-installed window latches offer minimal resistance — many can be defeated with a butter knife or a simple jolt. Upgrading to proper window security locks and reinforcing vulnerable panes with security bars is one of the highest-return investments a homeowner can make. This guide covers the most effective options available, broken down by window type and threat level.

Why Factory Window Latches Fail

Most residential windows ship with a simple sash lock — a small crescent-shaped latch that keeps the window closed but was never designed to resist forced entry. These latches are made from lightweight zinc alloy, and the screws holding them are typically only half an inch long. A determined intruder can pop them open in seconds by applying lateral pressure to the frame or by cutting through old weatherstripping.

Beyond the latch itself, older single-pane windows offer no meaningful resistance. Even double-pane glass, while harder to break quietly, provides little structural security if the frame is weak. The solution is layered: better locks plus physical barriers like pins, bars, or reinforced frames.

Best Window Security Locks by Window Type

Different window styles require different security approaches. Here is what works best for each:

• Double-hung windows: Keyed sash locks and window pins are the gold standard. A keyed sash lock replaces the factory latch and requires a key to open from inside or out. Window security pins — hardened steel rods drilled through the inner sash into the outer sash at a downward angle — prevent the window from being lifted even if the latch is defeated.
• Casement windows: These crank outward and are inherently more secure, but the locking handle can still be bypassed. A casement window lock with a keyed mechanism adds a second layer. Look for models with a multi-point locking system that engages at top, middle, and bottom simultaneously.
• Sliding windows: Insert a solid steel or hardwood bar in the track to prevent the window from being slid open. Combine this with a track lock or anti-lift pin that prevents the panel from being lifted out of the frame — a common bypass technique.
• Basement and ground-floor windows: These are highest-risk. Use both a keyed lock and a security bar or grille. Consider laminated glass film as an additional barrier against smash-and-grab entry.

Security Bars: Fixed vs. Removable

Security bars are among the most physically deterrent upgrades available. They signal to a potential intruder that forced entry will be noisy, time-consuming, and highly visible. However, choosing between fixed and removable bars is a critical safety decision.

Fixed security bars are permanently welded or bolted to the window frame or surrounding masonry. They offer maximum resistance but create a fire egress hazard. Building codes in many jurisdictions prohibit fixed bars on sleeping room windows for exactly this reason.

Removable or swing-away security bars are hinged and can be opened from inside with a quick-release mechanism. These satisfy fire safety requirements while still providing strong deterrence. Look for bars rated to withstand at least 1,500 lbs of outward force. Brands like Master Lock and Defender Security offer well-regarded options in this category.

Window security grilles are a more aesthetically refined alternative. Powder-coated steel grilles can be custom-fitted to any window opening and are far less industrial-looking than traditional bars while offering comparable strength.

Window Security Film: An Underrated Layer

No discussion of window security locks and physical barriers is complete without mentioning security film. 3M Safety Series and similar products bond to the inside of the glass, holding shards together when the pane is struck. A window treated with 8-mil or thicker security film can withstand repeated hammer blows that would shatter untreated glass instantly.

Film does not prevent a window from being broken, but it dramatically increases the time and noise required to create a usable opening — typically the two things that deter opportunistic intruders most effectively.

Installing Window Pins: A DIY Security Upgrade

Window security pins are inexpensive and can be installed in under ten minutes per window with a standard drill. Here is the basic process for double-hung windows:

1. Close and latch the window fully.
2. At a slight downward angle, drill through the inner sash and partway into the outer sash — do not drill all the way through.
3. Insert a hardened eyebolt or steel pin into the hole.
4. For a ventilation position, drill a second set of holes with the window open 4–6 inches.

This technique costs under five dollars per window and is one of the most effective single upgrades available. It is commonly recommended by law enforcement crime prevention officers.

Building a Complete Window Security Strategy

The strongest approach combines multiple layers: quality window security locks, physical pins or bars, security film on ground-floor windows, and sensor alarms on every accessible pane. Window vibration sensors and glass-break detectors integrate easily with most home alarm systems and add an electronic alert layer to your physical barriers.

Audit every window in your home by ground-floor vulnerability first. Any window that can be reached from the ground, a fence, a deck, or a tree branch within six feet deserves at minimum a keyed lock and a security pin. Higher-risk windows — isolated from street view, obscured by landscaping, or adjacent to a porch roof — should also receive bars or grilles.

Consistent, layered window security does not require a large budget. A full window security upgrade for an average home typically costs between $150 and $400 in hardware, with most of the work being straightforward DIY installation. That investment is a fraction of the average residential burglary loss, which the FBI estimates at over $2,600 per incident.