The front door is where you decide who comes into your home — and that decision is easiest to get right when you can see and speak to a caller before you open up. Door chains and spy holes are simple, inexpensive devices that put you in control at the threshold. This post explains the different types, how to fit and use them, how to spot a bogus caller, and — just as importantly — what a chain can and can't do. It's written with everyone in mind, but especially older and more vulnerable residents, who distraction burglars target most often.

Why the doorstep matters

Most of us focus on locks and bolts, but a good deal of crime against householders happens at the open door. Distraction burglary — sometimes called "bogus caller" crime — relies on talking their way in: a fake utility worker, a council inspector, someone claiming to need water for an overheating car. Once inside, one keeps you talking while another searches the house.

The defence isn't a stronger lock. It's the ability to deal with a caller without fully opening the door, and the confidence to say no. That's what chains, limiters and viewers are for. They complement your main locks — for the locks themselves, see our lock replacement service.

Door chains and limiters

These let the door open only a few inches, so you can talk to a caller and see them while keeping a barrier between you.

Door chains

The familiar sliding chain runs in a track screwed to the door and frame. You can engage it, open the door a crack to speak, and decide whether to let the person in. It's cheap, widely available and easy to use.

The weakness is that a chain is only as strong as its fixings. If the screws are short or driven into soft timber, a hard shove can rip it out. A chain is a deterrent and a conversation aid — not a lock.

Door limiters and restrictors

A door limiter (also called a restrictor or door bar) does the same job with a hinged metal bar instead of a chain. It's generally stronger and harder to force than a chain, because the load spreads across a solid bar and a more substantial bracket. For anyone who wants more reassurance than a chain offers, a limiter is the better choice.

Whichever you fit, the golden rules are the same: fit it well, into solid material, with long screws, and engage it before you open the door to anyone you don't know.

Spy holes and door viewers

Seeing a caller before you open the door changes everything. If you don't like the look of a situation, you simply don't open up.

Traditional door viewers

A traditional spy hole is a small wide-angle lens fitted through the door. It gives a fish-eye view of the doorstep. They're cheap and reliable, though the small lens can be hard to use for anyone with limited eyesight, and the viewing angle can leave blind spots close to the door.

Digital door viewers

A digital door viewer replaces the lens with a small camera and an internal screen. The larger, brighter image is far easier to see, especially for older residents, and many record a snapshot of each caller. For anyone who struggles with a tiny traditional lens, a digital viewer is a worthwhile upgrade.

Video doorbells

A video doorbell goes a step further: you see and speak to a caller from your phone or a screen, even from another room — or away from home. For someone who finds it difficult to get to the door quickly, this means you never have to rush to a caller you can't see. Many also record footage, which is useful if a bogus caller turns up.

Used together — a viewer or doorbell to see who's there, a chain or limiter for when you do open up — these devices give you genuine control of your doorstep.

How to deal with callers safely

The hardware only helps if you use it with a few sensible habits. Share these with any older or vulnerable relatives — they're the heart of doorstep safety.

Look before you open. Use the viewer or doorbell every time. If you can't see who it is, don't open.
Put the chain or limiter on first, then open the door a crack to speak.
Always ask for identification. Genuine callers from utilities, the council or any company carry ID and will happily show it. Take the card, close the door, and check it.
Never feel rushed. A real official will wait while you verify them. Pressure to act quickly — "I just need to come in for a second" — is a warning sign.
Use a password scheme if your utility offers one. Many providers let vulnerable customers set a password that genuine callers must give.
If in doubt, keep them out. You're never obliged to let anyone in. Phone the company on a number you look up yourself — not one the caller gives you — to confirm before opening.
Don't keep large amounts of cash at home, and never let a caller "watch" while you fetch money.

Distraction burglars rely on politeness and uncertainty. Slowing the whole thing down defeats most of them. It also helps to understand how burglars think more broadly — we cover that in how burglars open doors.

The limits of a door chain — be realistic

It's important to be honest about what a chain can't do, because over-trusting one is its own risk.

A chain is not a lock. It won't stop a determined intruder forcing the door, and a poorly fitted one fails to a single hard shove.
It can give false confidence. Some people open the door on the chain to a stranger and then take it off because the person seems friendly. The chain only protects you while it's engaged.
It needs solid fixings. On a flimsy door or rotten frame, even a good chain has nothing to hold onto. The fixing is everything.
It complements, never replaces, your main locks. Your front door still needs proper deadlocking — a BS3621 mortice on timber, or a multipoint with an anti-snap cylinder on uPVC and composite. A chain on a weak door is window dressing.

So treat a chain or limiter as a doorstep tool for managing callers, sitting on top of a properly secured door — not as a substitute for one.

What it costs

Doorstep security is among the cheapest home-security spending you'll ever do.

Door chain or limiter: typically £5–£20 for the hardware.
Traditional door viewer: similar, a few pounds for the lens.
Digital door viewer: more, but still modest, and a genuine help for poor eyesight.
Video doorbell: varies widely by model and whether you want recording or a subscription.

Fitting is quick. A locksmith can install a chain, a limiter and a viewer in a single short visit, and check that your main locks are up to scratch while they're there. If a door has been forced or tampered with, our burglary repairs service can put it right and add doorstep protection at the same time.

A word for family and carers

If you look after an older or vulnerable relative, the doorstep is one of the highest-value places to help. A digital viewer they can actually see, a sturdy limiter that's easy to operate, and a clear, rehearsed routine — look, chain on, ask for ID, no rush — together make a real difference. Walk through it with them more than once, and put a reminder note by the door if it helps.

When to call a locksmith

It's worth calling a locksmith if:

An older or vulnerable household member needs an easy way to see and screen callers.
Your existing chain or viewer is loose, broken or fitted into weak material.
You've had a suspicious or bogus caller and want to feel more secure at the door.
You want a doorstep upgrade fitted properly, with the fixings done into solid material.
You're not sure your main locks are strong enough beneath the doorstep extras.

A locksmith will fit chains, limiters and viewers correctly, advise on the best option for the household, and make sure the door itself is properly secured. If you're in Manchester — including Withington and across the city — and want your doorstep made safer, get in touch and we'll sort it in a single visit.

Door chains and spy holes — answering the door safely