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Doors & securitySep 10, 202610 min video

How to install a smart deadbolt

Swap an old deadbolt for a Wi-Fi smart deadbolt on a door that’s already drilled for one, then set it up in the lock’s app.

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Step by step

What you’ll need

  • Phillips screwdriver, used by hand: a drill can damage the lock
  • Tape measure
  • Fresh alkaline batteries, usually four AA
  • Phone with the lock’s app and your 2.4 GHz Wi-Fi password
  • Chisel and hammer, if the new strike needs a deeper pocket

Before you start

  • Measure the door. Most smart deadbolts need a door 1-3/8 to 1-3/4 in thick, a 2-1/8 in face hole, a 1 in edge hole and a 2-3/8 or 2-3/4 in backset (edge to center of the big hole). Thicker doors need the maker’s thick-door kit. Smaller holes can be opened up; bigger ones won’t work.
  • Lock the old deadbolt with the door shut. If you have to push, pull or lift the door, tighten the hinges or move the strike first: a motor stalls where your hand just pushes through.
  • Check your phone’s Wi-Fi at the door. The lock needs a 2.4 GHz network, and a weak signal drains its batteries, so add an extender if it’s poor.

  1. Take off the old deadbolt

    The thumbturn on the inside of a white door turned straight up, with a screwdriver in the right-hand of its two screws.

    Turn the thumbturn halfway to reach both inside screws, and hold the outside piece so it doesn’t drop. Then remove the two edge screws and pull the bolt.

    Watch this step (1:05)

  2. Swap the strike

    A hand driving the lower screw of a new Schlage strike plate on the door frame with a red-handled screwdriver, the new lock's inside unit on the open door beside it.

    Replace the old strike with the one in the box, plus its reinforcement plate if it has one. The bolt needs a clean pocket at least 1 in deep; chisel it out if not.

    Watch this step (5:47)

  3. Set and fit the new bolt

    A new deadbolt fitted in the edge of an open white door, its square slot centered in the big round hole, with a hand pressing its faceplate in.

    Set the bolt to your backset (many twist out from 2-3/8 to 2-3/4 in) so its slot sits centered in the big hole. Screw it in with TOP facing up.

    Watch this step (3:25)

  4. Mount the outside keypad

    A hand holding a keypad lock against the outside of an open door, its flat tailpiece and cable passing through the big hole into the deadbolt's slot.

    Feed its cable through under the bolt, fit the tailpiece into the bolt’s slot, and push the keypad flat to the door.

    Watch this step (3:39)

  5. Fit the mounting plate

    A screwdriver tightening a gold mounting plate marked TOP over the deadbolt hole on the inside of a door, with the lock's cable and plug hanging below it.

    Put it on the inside, marked side against the door and TOP up, with the cable through its hole. Start both screws by hand, square up the keypad, then tighten them with the screwdriver.

    Watch this step (4:01)

  6. Connect the inside unit

    Hands holding the inside unit of a smart lock and pushing its cable plug together in front of the mounting plate on a white door.

    Plug in the cable; it only fits one way. Turn the thumbturn to unlocked so it meets the tailpiece, and tuck the cable above the spindle so it can’t pinch. Screw the unit on, then turn the thumbturn: the bolt should run smoothly.

    Watch this step (5:00)

  7. Add the batteries

    A hand holding a battery holder loaded with four Duracell AA batteries in front of the opened inside unit of a smart lock.

    Load the battery holder and slide it back in with the batteries facing the door. Skip lithium and rechargeables; they can die with little warning.

    Watch this step (5:57)

  8. Test it with the door open

    A Schlage keypad on an open door, its check-mark light glowing blue and the bolt sticking out of the door's edge.

    Keep the card with the default codes. With the door still open, lock it from the keypad and unlock it with a code, letting any setup routine finish. Then shut the door and throw the bolt by hand: it should slide in without a push on the door.

    Watch this step (6:14)

  9. Keep the key safe

    Two hands holding a Schlage keypad up in front of an open white door, its round key cylinder centered below the number pad.

    With dead batteries, the key is your only way in unless the lock has a 9-volt or USB jump-start terminal. Keep it on your keyring or with someone you trust, and get a spare cut.

    Watch this step (6:49)

  10. Pair it with the app

    The inside unit of a smart lock with its cover off, showing the thumbturn and a small round black button to its right, with a blurred label above.

    Add a lock in the lock’s app and scan its QR code. Press and release the pairing button under the inside cover (holding it can reset the lock), join your 2.4 GHz network and set your own code.

    Watch this step (7:16)

  11. Let it learn your door

    The outside of a slightly open white door with a Schlage keypad, its check mark lit blue and the bolt extended from the door's edge.

    When the app asks, open the door slightly and start the calibration. Wait until the bolt stops moving, then close the door and lock it from the app.

    Watch this step (8:35)

Mistakes to avoid

  • Blaming the lock for a strike problem: if it works open but jams shut, rub lipstick on the bolt, throw it with the door closed, and file or chisel where it marks.
  • Forcing a crooked inside unit flat with its screws: back them off, set the thumbturn to unlocked, re-tuck the cable and refit it.
  • Fighting a combined 2.4/5 GHz network: if the lock won’t connect, pause the 5 GHz band while you set it up.