Secure ground floor windows: lock before siren or film

You secure ground floor windows by locking the sash before you buy a hanging siren or a roll of mirror film. UK police pages put a key-operated lock, used before bed and before you leave, ahead of noise and ahead of film. A handle alarm does not lock anything, and the silver film in this range is daytime privacy film, not the security film those pages sit next to laminated glass.

In short

Lock the sash before bed and before you leave. A hanging siren does not hold it, and the silver rolls here are daylight privacy film, not security film beside laminated glass.

The police order is a lock you actually use

Metropolitan Police puts key-operated locks on opening-out windows and other accessible windows, and it tells you to use them at those two moments. A casement, a roof light, a sash, and a tilt-and-turn do not share one piece of hardware, which is why Avon and Somerset Police splits the fitting by type. ProtectUK says accessible windows get key-operated locks unless the window is a fire escape.

The National Protective Security Authority treats a cockspur or an espagnolette you cannot lock as a weak thing to rely on. The step up is a lockable cockspur or a multi-point espagnolette that holds the sash. When that lock is engaged, the usual way past it is damage, not a quiet bypass. No listing here is claimed to stop a burglary or to satisfy an insurer's wording.

On amazon.co.uk on 15 October 2026, keyed handles in the window handle comparison ran from about £4.99 to £24.80. If you have not measured the spindle, the Home Secure multi-spindle locking handle, ASIN B0D81HFS43, was about £7.99, with 4.5 stars from 2,213 ratings. The title says it locks and comes with keys. Spindle lengths are not numbered, so you still seat them in the gearbox.

One UK review said it did not fit, and several said the supplied screws were the wrong length. Measure the screw centres before you order, because many modern espag plates are 43 mm apart and a sash that differs will not take that plate. A lever at this price does not make the window PAS 24. The Met page reserves PAS 24:2022 for a replacement window. PAS 24 belongs to the whole window, not to a new lever.

What a hanging handle alarm adds

A hanging handle alarm is a battery siren that makes a noise when its sensor trips. It does not throw a bolt, phone a monitoring centre, or keep a sash closed. On 15 October 2026 the hangers in the handle alarm comparison sat at about £8.39 to £10.99. Buy that noise after a window you can lock has been locked. On a uPVC door, lock it and take the key off the glass before you think about a siren.

Metropolitan Police mentions a stick-on vibration alarm, especially on ground-floor glass that is out of sight. Greater Manchester Police's stick-on is a glass pad as well. Those lines describe a sensor fixed to the pane. Wireless on the hanging listings means there is no bell wire. It does not mean a monitoring centre.

Two Defender listings at £9.95 use different sensors. EL00002, ASIN B01BNLDBCI, is a magnetic-field sensor at 125 dB for 30 seconds, on three AAA cells, for an internal door, and window use is not claimed. EL00237, the Ultra Slim, ASIN B0DZ7763YH, is a vibration sensor at 125 dB with a 7-second exit delay and three LR44 cells, and window use is not claimed there either. A Sold Secure Gold line on that listing is a seller's bullet, not a certificate in this file. If the sash is unlocked, either siren can shout while the window still opens.

Security film, mirror film, and a glass pad

Metropolitan Police puts laminated glass or security film on ground-floor and accessible windows, beside the locks. Security film in that sentence sits with laminated glass. It is film meant to stay with the pane if the glass breaks. The rolls in the window solar film comparison are silver one-way mirror film for daytime privacy. They are not EN 12600 safety film, and this research did not break a pane to see what they did.

The Window Film Company states the lighting rule: there is no true two-way film. The mirror effect needs the brighter side outside, which is daylight. After dark, with the room lights on, the brighter side is indoors and the mirror reverses. Curtains or blinds are the night cover. A ground-floor room that looks private at noon can show the interior at 8pm.

On amazon.co.uk on 15 October 2026, mirror rolls started at about £6.99. The rabbitgoo one-way film at 44.5 by 200 cm, ASIN B07BFTRLTK, was £9.99, with a claimed 90 percent UV block and an 89 percent infrared block, and 4.0 stars from 62,453 reviews. Those percentages are listing claims, not an EN 410 test. The listing wants flat, clean, smooth glass.

A glass pad, a mirror roll, and security film are three purchases. Lock the window first, then decide if daytime privacy on a measured pane is worth a roll. Measure the glass before you order, because a short roll will not cover a wide casement.

Night, keys, and the escape window

Close the sash fully, lock the cams, and take the key off the glass before you go upstairs and before you leave. A lock left open because the key is a nuisance does nothing for the hours you are asleep or out.

ProtectUK says the key for an escape window must be reachable in a fire, and it must not be easy to reach from outside. A key left in the handle, or a key on the sill in sight of the glass, fails the second half. A hook inside the room, beyond arm's reach through a broken pane, is the compromise most households can keep. The hook has to be obvious in smoke, so a drawer in another room fails the fire half of the same advice.

A restrictor limits a window you still want to ventilate. It does not stand in for a lock, and a keyed handle does nothing while the sash is ajar, because the cams are not holding a closed window. Night air and a shut room are two positions. Choose one before you leave the room.

Metropolitan Police says to lock upper windows too. A first-floor casement over a flat roof or a porch is accessible even though you sleep upstairs. RoSPA still wants upstairs windows locked or restricted, because a fall from an open sash is a separate risk. An escape window is the one you do not secure in a way that traps you. If you replace the frame, ask for the whole window to a standard such as PAS 24:2022, fixed as that design expects. A lever, a siren, and film do not turn the old sash into that test.

What not to buy for this job

A draught seal is rubber or foam for a gap you can feel with your hand. It can quiet a whistle on a window that still closes and locks. It does not hold the sash. If the window opens too easily from outside, a seal is the wrong packet.

A window box is a planter. Plastic and timber differ in weight and drainage, and neither keeps a casement shut. Drilling a uPVC frame to hang a box can mark the window you are trying to look after.

Skip the hanging siren when the window has no working lock. Skip the silver roll when you wanted the film a police page pairs with laminated glass. Skip both when the lever spins and the gearbox does not drive. That fault is covered in when a window handle spins and nothing locks.

This page does not rank a siren against a keyed handle. Prices are amazon.co.uk shelf prices on 15 October 2026 and will move. Products Compared did not laboratory-test these products. A product link on a comparison may earn us a commission at no extra cost to you.