Do You Need a Deadbolt and a Knob Lock?

Strictly speaking, no. If you wonder do you need a deadbolt and a knob lock, the deadbolt provides nearly all the physical security against forced entry. A standard knob lock offers minimal protection and increases accidental lockouts. Pairing a deadbolt with an unkeyed passage latch is often the better choice.

Residential building codes and insurance policies require a sturdy deadbolt for exterior doors, but they rarely require a keyed handle. Keeping both keyed can even create egress hazards during emergencies, though many builders still install both out of habit.

What is the difference in security between both locks?

A deadbolt extends a solid steel bolt at least one inch into the door jamb. Because this bolt does not have a spring mechanism, physical force cannot depress it from the outside.

In contrast, a knob lock uses an angled spring latch designed primarily to keep the door closed against wind and drafts. While knob locks contain basic locking pins, the latch itself remains vulnerable to direct physical manipulation.

Deadlocking plunger: A small metal pin next to the spring latch designed to prevent credit card shimming when the door is shut.

Can a knob lock be bypassed without a key?

Knob locks are notoriously simple to bypass with basic hand tools. Because the knob houses the lock cylinder inside a hollow exterior shell, an intruder can wrench the entire knob off using a pipe wrench or channel locks.

If the strike plate is misaligned, a thin plastic card or screwdriver can push back the spring latch in seconds. Reading about whether can a smart lock be picked or bumped shows that standard brass cylinders in entry knobs provide minimal resistance against common bypass tactics.

A single solid kick often shears a standard knob latch right out of the strike jamb.

Why do so many exterior doors have both locks installed?

Most homebuilders drill two holes into exterior entry doors as a standard construction practice. Selling pre-hung doors with two boreholes gives homeowners flexibility, so hardware manufacturers bundle keyed entry knobs and deadbolts together in matched sets.

Many residents also appreciate having a temporary privacy option during the day. They leave the heavy deadbolt disengaged during the afternoon while working in the yard, relying solely on the knob latch to keep casual visitors from turning the handle.

What problems happen when you use both locks together?

Using both locks introduces safety risks and daily frustrations that deadbolts alone avoid. The most frequent issues include:

• Accidental home lockouts: Turning the thumb-turn on the inside knob locks the latch before you pull the door shut without your keys.
• Delayed emergency escape: Fumbling with two separate mechanisms in smoke or panic slows down egress when seconds matter most.
• Automation system conflicts: Setting up what is auto lock and should you use it on a smart bolt fails if someone locks the manual knob underneath.
• Key management confusion: Carrying separate keys or rekeying two cylinders adds cost when exploring how to rekey or change locks after moving into a property.

What should you replace a keyed knob with instead?

The ideal setup for any exterior door is a Grade 1 or Grade 2 deadbolt paired with a non-locking passage lever or knob. The passage latch handles the mechanical work of holding the door flush against the weatherstripping, while the deadbolt handles all physical defense.

This setup guarantees that you can never lock yourself out by accidentally twisting a thumb-turn on your way out the door. If the door closes behind you, turning the handle opens it immediately unless you deliberately secured the deadbolt with your physical key or electronic keypad.

Common questions about entryway door locks

Door security setups generate distinct questions about safety standards, apartment rules, and building codes.