How to Lock a Window If the Lock Is Broken

A broken window lock is more than an inconvenience — it’s a security vulnerability and, depending on the window, it can let drafts and moisture into your home. If your window lock has failed and you can’t get it repaired right away, there are several temporary solutions that will keep your window secured until a proper fix is in place. Here’s what actually works, what to avoid, and when it’s time to call in a professional.

Temporary Solutions That Work

Window security bar or charley bar. This is the simplest and most effective temporary fix for sliding windows. A charley bar is an adjustable metal rod that sits in the bottom track of a sliding window, physically preventing it from opening. You can pick one up at most hardware stores for under twenty dollars, or in a pinch, a cut-to-length wooden dowel or broomstick handle placed in the track does the same job. Just make sure it fits snugly — too short and it won’t hold.

Window pin or nail method. For double-hung windows (the kind that slide up and down), you can drill a small angled hole through the inner sash and partially into the outer sash where they overlap, then insert a nail or pin. This physically locks the two sashes together so the window can’t be opened. It’s a classic approach that’s been used for decades and it’s surprisingly effective. Use a nail that can be easily removed so you can still open the window when needed.

Aftermarket window latch or clamp. Hardware stores carry universal window locks and sash clamps that mount with just a couple of screws. These aren’t as elegant as the original hardware, but they do the job. Just make sure whatever you buy is rated for your window type — a clamp designed for a single-hung window won’t work properly on a casement.

Hinged wedge lock. For sliding windows and doors, a hinged wedge lock screws onto the upper track and flips down to block the window from sliding open. These are inexpensive, easy to install, and more secure than a dowel because they’re physically attached to the frame.

What to Avoid

Don’t use tape, adhesive products, or anything that could damage the frame or leave residue. We’ve seen customers use everything from duct tape to super glue — these don’t provide real security and they often make the eventual repair harder (and more expensive). Also avoid screwing the window shut permanently. It might seem secure, but you’re creating a fire safety hazard. Every bedroom window should be operable as an emergency exit.

“A temporary fix is fine for a few days, but I’ve walked into homes where someone put a dowel in the track three years ago and just left it. Meanwhile the lock mechanism has corroded, the track has debris built up, and now we’re looking at a bigger repair. The sooner you address the actual lock, the simpler and cheaper the fix.”

When to Get the Lock Properly Repaired

All of the methods above are stopgap measures. They’ll keep your home secure in the short term, but they’re not a permanent substitute for a functioning window lock. A properly working lock ensures the window seals tightly against weather, operates smoothly, and meets building code requirements — especially important if you ever sell your home or need to pass an inspection. If your window lock is broken, the most reliable move is to have the lock mechanism itself repaired or replaced by someone who can match the right hardware to your specific window.