Security Vs. Safety

One question I am often asked when installing a new deadbolt “Fresh install”, where there was no lock there before, is – should we buy a single cylinder or double cylinder deadbolt to lock the door.

A single cylinder deadbolt has a keyhole on the outside and a thumb turn on the inside whereas a double cylinder deadbolt has a keyhole on both the inside and outside of the door. (See photo).

The pros and cons of these locks, in the simplest terms, is as follows.

In the photo you can see that the back door has plate glass windows.  A thief can break one square, reach in, and turn a thumb-turn on the inside to let himself in, thus, the double cylinder deadbolt is more secure.

The downside of this type of lock is that it is also a fire hazard, as it can stop someone from exiting the building in an emergency if they don’t have a key.

So as you can see, these locks are a matter of security vs. safety and you should be the judge on what type of lock to buy.

If you go with the double cylinder deadbolt I recommend you keep a copy of the key near the door in case of an emergency, hidden out of site but easy to access.

If the door goes to a rental, use a single cylinder deadbolt as double keyed deadbolts are illegal on rentals in most cases.

Be well, be safe, and if you have any questions, feel free to send us an email.

~Michael

Owner, All About Locks & Safes

Chico Mobile Locksmith Company