What counts as a secondary lock
The main lock on an entry door is usually a deadbolt, sometimes paired with a latch set in the handle. Everything else that people bolt, screw or stick onto the door belongs to the secondary category: door viewers, chains, swing bars, surface bolts, door jammers, wedge stops, strike plate reinforcements and the camera doorbells that have become common in recent years.
These devices are not alike. Some help you decide whether to open the door at all, which is a safety decision. Some limit how far the door can open when it is unlocked. Some strengthen the point where force is actually applied. A few do very little but are inexpensive to try, and a few create new problems, such as slowing you down in an emergency.
This page is general guidance for homeowners and renters across Broward County. It does not replace the rules of your building, your lease or your insurance contact, and it avoids describing ways to defeat any device. The aim is to help you decide which small additions are worth having next to the main lock you already own.
The peephole: a decision tool, not a barrier
A door viewer, the small lens most people call a peephole, does one job: it lets you see who is outside before you open up. It adds no strength to the door at all. Its value is in the decision it supports, because the safest door is the one you did not open to a person you cannot identify.
Choose a viewer with a wide field of view so you can see someone standing off to the side, not only directly in front. Check that the lens is clean and not scratched, and that the height suits the people who live in the home. A viewer set for an adult is useless to a child, and a second one at a lower height may be worth considering where children are old enough to answer the door.
Think about lighting too. A viewer shows little if the landing is dark. A porch light or hallway light that works reliably makes the viewer far more useful. Also keep in mind that a cover on the inside should slide or flip easily, and that the hole through the door should be neatly finished so that it does not weaken the surrounding wood or metal.
Door chains and why they disappoint
A traditional chain lets the door open a few inches so you can talk to a caller without letting them in. That sounds sensible, and it makes people feel safer. The trouble is that a chain depends on small screws in the door frame, often short ones that bite only into trim. A hard shove can pull them out, and the door swings wide.
A chain is therefore a tool for politeness and for slowing an unwanted visitor, not for stopping a determined one. It does not secure an unattended home, because you can only fasten it from the inside while you are there. It can also be a nuisance for people with limited dexterity, who may find it hard to release in a hurry.
If you like the idea of a chain, treat it as a supplement and make sure the hardware is fixed into solid framing with proper length screws. Better yet, consider whether a camera doorbell or a good viewer would meet the same need, since both let you decide before you open the door a crack. Our article on upgrading the strike plate against kick ins addresses the stronger and more important part of the door.
Swing bars and the idea of the second latch
A swing bar, sometimes called a night latch or a security bar, is a heavier cousin of the chain. It is a metal arm that pivots from a plate on the door and drops into a catch on the frame. Fitted well into solid wood or reinforced mounting, it offers a firmer stop than a chain and can be fixed in place while you are home.
Like a chain, it works only when someone is inside, and it relies on the screws and the framing more than on the bar itself. If the plates are mounted with short screws into thin trim, the device is little better than a chain. If the mounting is strong, it becomes a useful second latch for nighttime, a time when many households want an extra line of defense.
Look at the way the bar operates. It should be easy to release with one hand, in the dark, by someone who is startled or in a hurry. Practice that action with every adult and older child in the home. A device that nobody can operate calmly in an emergency is a hazard, not a protection. If you rent, ask your landlord before you drill into the frame.
Surface bolts, jammers and drop bars
Surface bolts are simple sliding bolts mounted on the inside face of a door. They can add a fixed point at the top or bottom, which helps on doors that tend to flex. Their effectiveness depends on the quality of the bolt, the thickness of the door and the solidity of the frame that receives the bolt.
Door jammers and drop bars are even more basic, bracing the door from the inside with a rigid piece set against the floor or into brackets. They can be very strong for a night at home, but they obviously cannot be used when you are out, and they can slow your exit during a fire. They are wisely treated as a temporary or nighttime measure, and only in a way that the whole household understands.
A word about portable travel devices: some people carry small door wedges or travel locks for hotels and short stays. These can give peace of mind in an unfamiliar room, but they have the same limits as other secondary devices and must never be allowed to block an emergency exit. Use them with care, and never on a door that other people may need to use in a hurry.
Sliding doors, windows and the other ways in
Most of this article focuses on the front door, but a secondary lock on that door does nothing for the rest of the home. In Broward County, many houses and condos have sliding glass doors that open onto patios, and those doors carry their own simple secondary devices such as bars that sit in the track. Our guide to sliding glass door locks covers how those work.
Windows deserve the same attention. A window latch that is loose or painted over gives an easy path inside, and ground floor windows near hidden corners are the usual concern. Read window lock upgrades to see what is reasonable to add without damaging the frame or blocking an escape route.
Humidity matters here as well. Metal tracks collect grit and salt residue near the coast, and a device that sits in a dirty track may not seat properly. Clean the track gently on a regular schedule so that any bar or pin you rely on actually fits where it should.
Think about the garage as well. A door between a garage and the house is often treated as less important than the front door, even though it is just as much an entrance. Our piece on garage entry door security explains why that connection deserves the same care as any other exterior door.
Camera doorbells and smart viewers
A camera doorbell does what a viewer does, with extra features: you can see and speak with a visitor from another room or from your phone, and some models keep a short record of who came. For people who cannot easily reach a door viewer, such as wheelchair users or small children, a screen is a real accessibility gain.
They also have limits. They depend on power or batteries, a wireless connection and a working app. They can fail during an outage, and hot, humid weather can shorten battery life and cloud the lens. Some residents find camera placement is limited by building rules, so check with your building manager or HOA before attaching anything to a shared wall or door.
Think about privacy as well. A camera that faces a shared corridor may record neighbors, which can cause friction and may be restricted. Pointing the lens only at your own doorstep is courteous and often required. For options that pair a lock with a screen, take a look at our smart locks page, then decide how much technology you want to depend on.
Whatever you choose, test it in realistic conditions: at night, in rain, and with your hands full of groceries. A device that works well in daylight but fails in a thunderstorm will disappoint exactly when you need it. Keep a plain mechanical way to see and to lock the door as a backup for any gadget.
Where the real strength of a door comes from
It helps to remember that secondary locks are accessories. The strength of an entry door comes from the door slab, the frame, the hinges, the strike plate and the deadbolt working together. A solid door in a sound frame, with long screws reaching the structural stud behind the trim, does more than any number of chains.
Hinges deserve a note. Loose or short hinge screws let a door be pried or lifted from the hinge side, bypassing the latch altogether. Replacing a few screws with longer ones that reach the structure behind the frame is a modest job with a lasting effect, and a technician can check them while looking at your lock.
The most common failure point is not the lock but the frame around the strike plate. When someone kicks a door, the wood around the bolt splits, and the door opens even though the bolt was thrown. Reinforcing that spot, along with the hinge side, gives a lasting improvement. That is why a careful locksmith will look at the whole door when you ask about a single device.
If you are unsure of the condition of your hardware, a sensible first step is to have it looked at. Our guide are your locks good enough offers a checklist, and describing your door by phone on the house lockout and rekey page route is a good way to get tailored suggestions.
Rentals, condos and what you may change
If you rent or live in a condo, your freedom to add hardware is limited. Drilling into a door or frame may violate a lease, and doors facing a common hallway are often controlled by the association because of fire rules and emergency access. Requirements vary, so ask your landlord, building manager or HOA before installing anything permanent.
Renters have good options that need no drilling. Door viewers sometimes screw in through a pre existing hole, and some devices clamp or brace without any permanent change. A battery powered camera that sits on a shelf or hangs on a hook can serve some of the same purposes. Our renters guide to lockouts includes more thoughts on what a tenant can reasonably ask for.
Between tenants, the sensible step is to have the main locks rekeyed, which is routine and invisible to the door. Secondary devices added by a former occupant, such as chains with weak screws, are worth checking and replacing as part of the same visit. A fresh look at the door at move in beats finding out about its flaws later.
If you are the one who manages the property, keep a simple note of what is installed on each door and who approved it. That record helps the next resident, speeds up any repair visit, and avoids arguments about who added a device and whether it was allowed.
Safety first: never trade away your exit
The most important rule about secondary locks is that they must never make it harder to leave in an emergency. A fire, a medical problem or a sudden need to get a child out should never require a key, a tool or a puzzle. Choose devices that open with a single obvious motion from the inside, and make sure all family members know how.
Think about visitors and caregivers as well. A babysitter, a relative or a home health aide should be able to leave without guidance. If a device needs explanation, put a short reminder where it is easy to see, or choose something simpler. In multi unit buildings, remember that firefighters and neighbors may need to reach your door too.
Finally, avoid the temptation to stack devices until the door becomes a puzzle. More hardware is not always more safety. A sturdy deadbolt, a well installed strike, a clear view of the visitor, and a habit of not opening the door to strangers are usually enough. Everything else should earn its place by solving a specific problem.
A practical plan for your own front door
Start with the basics. Confirm that the door closes squarely, that the deadbolt extends fully, and that the strike plate is anchored with long screws. If any of those are off, fix them before adding accessories. A technician can check these points when you call, and the work and the price are explained before it begins.
Then address how you decide who to let in. A good viewer or a camera doorbell, with adequate lighting, makes this practical. Add a chain or swing bar only if you will use it, if it is mounted into solid framing, and if everyone in the household can release it without trouble in an emergency. Skip anything that adds clutter without solving a problem.
Finally, think about the periods when the home is empty. Secondary bars and chains do nothing then, so the main locks, the keys and your habits carry the weight. Our vacation home security checklist shows how to prepare a home for time away, and the finished work from any installation should be tested with you before the technician leaves.