Types of Door Locks: Which Lock for Which Door

Most Calgary homes need two kinds of lock on an exterior door: a latch in the handle that keeps the door closed, and a separate deadbolt that keeps it locked. The handle lock (a knob, lever or handleset) is a convenience. The deadbolt is the security. Interior doors need only a latch, or a simple privacy lock on bedrooms and bathrooms.

That one split answers most of the question "which lock for my front door". The rest is detail: single or double cylinder, keyed or keypad, and whether your house is a 1960s bungalow with its original hardware or a new build with whatever the builder bought in bulk. This guide goes through each lock family, says what it is good for, and matches it to the door it belongs on.

What are the main types of door locks used in homes?

The lock families a homeowner meets are knob locks, lever sets, handlesets, deadbolts (single and double cylinder), mortise locks, rim or night latches, keypad and smart deadbolts, and privacy and passage sets. Each does a different job, and several are normally paired on one door.

Knob and lever locks are the handle-and-latch type. A spring-loaded latch holds the door shut, and a key or button locks the handle. Handlesets are the same idea in a larger package, a grip handle with a thumb latch, common on front doors. Deadbolts are a separate lock with a solid steel bolt you turn by key or thumb-turn, and they do not spring back. Mortise locks are a boxed lock body set into a pocket cut in the edge of the door, combining latch and deadbolt in one unit. Rim latches mount on the inside surface of the door instead of inside it.

Keypad and smart deadbolts replace the key with a code, a phone or a fingerprint, and are covered in our smart lock guide. Privacy sets (a button or turn lock for bathrooms and bedrooms) and passage sets (no lock at all, just a latch) belong on interior doors only.

Is a knob lock enough to secure a front door?

No. A knob lock alone is the weakest common setup on an exterior door, because its latch bolt is short, spring-loaded and often held in place by a thin cylinder and a handle you can twist or pry. It keeps a door closed in wind. It does not keep a determined person out.

The latch is angled on one side so the door can close on its own, and that angled tongue is also its weakness. On a poorly fitted door with a gap between the door and the frame, a flexible card or a thin tool can push the tongue back. The knob itself is a second problem: it sits proud of the door, so a hard twist or a few blows can break the cylinder out of its housing, and the latch is gone with it.

A deadbolt solves both. The bolt is a solid steel cylinder, usually 25 mm (1 inch) of throw on a good one, and it does not retract unless the key or thumb-turn moves it. If your front door has only a knob or lever lock, adding a deadbolt is the single most useful upgrade you can make. For how to judge the deadbolt you buy, see our guide to deadbolt grades. A standard residential deadbolt installed typically runs $60 to $150, and a high-security one $150 to $250.

Which lock should go on a front door?

A front door should carry a deadbolt plus a handle lock: a single cylinder deadbolt above a knob, lever or handleset. The deadbolt does the securing, and the handle lock gives you a latch that works when you are home and the deadbolt is open. A keypad or smart deadbolt is a reasonable swap for the key-operated one.

Single cylinder means a key on the outside and a thumb-turn on the inside, which is what nearly every house should have. On a solid wood, steel or fibreglass front door, the deadbolt's strike plate should be fixed with screws long enough to pass through the jamb and into the framing stud behind it. A strike plate fixed only with the short screws that come in the box bites into the thin jamb alone, and a kick can split it. Replacing them with 75 mm (3 inch) screws is a ten-minute fix that costs almost nothing.

Handlesets (a decorative grip with a thumb-press latch) are popular on Calgary front doors for looks, and they are fine paired with a proper deadbolt. Levers are easier to use with full arms of groceries, cold hands or arthritis, and a lever is the better choice if anyone in the house has limited grip. Which brand to buy is a separate question, covered in our Schlage versus Kwikset comparison.

What locks belong on a back door, patio door and garage man-door?

Back doors and garage man-doors get the same treatment as the front: deadbolt plus handle lock. Sliding patio doors are the exception, because a deadbolt does not fit them. They need a secondary lock such as a bar, pin or foot lock added to the factory latch.

Back doors deserve as much attention as the front because they are hidden from the street, so anyone working on one is less likely to be seen. A back door with a knob lock and nothing else is the usual finding. Giving it a deadbolt and a solid frame is worth more than any amount of attention to the front door. Our guide to sliding patio door and window locks covers the slider problem in full, and secondary locks for a slider are cheap, generally $15 to $60.

The man-door from an attached garage into the house is the one people forget. It is an exterior door in security terms, because anyone who gets into the garage has all the time they want to work on it. It should have a deadbolt, a solid-core or steel door, and a good strike plate. See attached garage security for the rest of the garage setup, including the overhead door itself.

A detached garage side door is the same story. Deadbolt, 3 inch strike screws, and a keyway you do not share with the house if you can avoid it.

Should you use a double cylinder deadbolt?

Usually not on a house. A double cylinder deadbolt needs a key on both sides, which stops someone reaching through a broken window pane to turn a thumb-turn. The cost is that you also need a key to get out, and in a fire that is a serious hazard.

The case for double cylinder is narrow: a door with glass within arm's reach of the lock, such as a sidelight or a door with a large window panel. The case against is strong. In a fire or other emergency, nobody in the house should be hunting for a key in the dark and smoke, and Canadian building and fire codes are written around the principle that exits open from the inside without a key or special knowledge. How those rules apply to a particular door in a particular house depends on the code edition and the door, so if you are considering one, check with the City of Calgary's building permit staff and with your insurer before you buy.

For most homes there are better answers to the glass problem. Replace the glass with laminated glass or fit a security film. Move the deadbolt further from the glass. Or keep a single cylinder lock and accept the trade. Another option is to fit a double cylinder lock and keep the key in the lock on the inside whenever someone is home, but that defeats the point and relies on everyone remembering.

If a garage door or back door has glass near the lock and you want a second opinion on the layout, a locksmith can look at the actual door in a few minutes.

Do interior doors need real locks?

No. Interior doors need a passage set (latch only) or a privacy set (button or turn lock) for bedrooms and bathrooms. A privacy lock is designed to be opened from outside with a thin pin or a flat tool in an emergency, which is exactly what you want when a child locks themselves in.

Do not put a keyed deadbolt on a bedroom or bathroom door. In a lockout, a child, an elderly parent or a guest can lock themselves in with no easy way out. Privacy sets cost very little, and swapping a stuck or loose one is a quick job.

There are a few interior exceptions. A home office, a gun cabinet room or a room where you keep valuables can justify a keyed lever lock. For a basement suite, the door between your space and the tenant's needs a lock that suits how the suite is set up, and Alberta's Residential Tenancies Act sets rules on landlord entry and on changing locks. Our guide to rekeying between tenants explains the landlord side.

When do mortise locks and rim latches make sense?

Mortise locks belong on older doors that were built for them, mostly pre-war inner-city homes. Rim latches (night latches) belong on the inside face of a door, often as a second lock on a door that cannot take a bored deadbolt, such as a thin or glazed door.

A mortise lock is a rectangular lock body that sits in a deep pocket cut into the edge of the door, with a latch, a deadbolt and sometimes a deadlatch all in one box. In Calgary you are most likely to meet one in an early twentieth-century house in an older inner-city neighbourhood such as Mount Royal, Sunnyside or Hillhurst, where some homes still have original or period hardware. They are robust, repairable and can last a century. They are also awkward: parts can be hard to source, and cutting a new mortise pocket in a door that never had one removes a lot of wood.

If you have a mortise lock that works, keep it. Rekeying or repairing is often better than replacing, and our rekey or replace guide walks through the decision. A rim latch, mounted on the surface of the door, is the practical answer when a door is too thin or too old to drill for a standard deadbolt. It is surface-mounted, so it is visible, but a rim lock with a deadlocking bolt adds real security without major surgery on the door.

What changes between a 1960s bungalow and a new build?

Older Calgary homes tend to have worn, mismatched hardware and sometimes shrunken or shifted doors, while new builds have consistent but entry-level hardware. The lock types are the same. What differs is what is already on the door, how well it fits, and what the frame is made of.

In a 1950s to 1970s bungalow, the original hardware may still be there, often a knob lock on the front and back with nothing else, or a builder-grade deadbolt that has been turned a hundred thousand times. Calgary's chinook cycles matter here. Freeze-thaw swings, dry winter air and the movement of a timber frame cause doors to drop slightly, so the bolt no longer lines up with the strike hole. A deadbolt that drags or will not throw is usually an alignment problem, not a lock problem, and our guide to doors that won't latch in a Calgary frost heave covers that. Old keys are worth rekeying, because you do not know who has copies.

In a 1990s to 2000s suburb or a new-build community, you generally get matching builder-grade hardware throughout: the same keyway on every exterior door, a deadbolt that is often entry-level, and strike plates held with short screws. It is a good base to upgrade, and the doors are usually in better shape. The thing to check is the garage man-door, which builders often fit with the cheapest hardware in the house.

In an inner-city condo, you may not own the lock at all. The suite door, frame and sometimes the cylinder belong to the building, and the board's rules decide what you can change. Check your bylaws before you buy anything.

On any of these, the cold matters. At -30 C, a lock cylinder that has taken on moisture can freeze, and electronic locks lose battery performance. Lithium batteries handle cold better than alkaline ones, and a graphite or dry PTFE lubricant is safer in a cylinder than a wet oil. See how to stop frozen door locks for the winter routine.

How do you choose the right lock for each door?

Start with the exterior doors and work inward. Every exterior door gets a deadbolt and a handle lock. Add a secondary lock to sliders. Fit the interior doors with privacy or passage sets only. Beyond that, the decisions are about convenience and condition, not about adding more locks.

Here is a short checklist that works for most Calgary homes:

• Front door: single cylinder deadbolt plus a lever, knob or handleset. Keypad or smart deadbolt if you want keyless entry.
• Back door: the same, and check the frame and strike plate.
• Attached garage man-door: deadbolt, solid-core or steel door, long strike screws.
• Sliding patio door: a secondary pin, bar or foot lock on top of the factory latch.
• Bedrooms and bathrooms: privacy sets, never a keyed deadbolt.
• Closets and hallways: passage sets.

A lock is only as good as the door and frame around it. A strong deadbolt in a hollow door with a split jamb is a weak setup, and a decent door with a worn latch is easier to fix than most people think. Before spending money, test the door: close it, lock it, and push on it. If the door flexes, the frame gaps or the bolt barely engages, fix that first.

Not sure which lock your doors need?

If you can see what is on the door but cannot tell whether it is worth keeping, a locksmith can usually tell in a few minutes, and sometimes the honest answer is that nothing needs replacing. A tight strike plate, a rekey or a swapped handle is often all it takes.

If you want a second pair of eyes, our residential locksmith team can check your front, back and garage doors, fit deadbolts, replace worn handle sets and rekey locks across Calgary, Airdrie, Cochrane, Chestermere and Okotoks. We are family owned and operated, and we would rather tell you a door is fine than sell you hardware it does not need. To book a visit or ask a question first, contact us.