The short answer
Decide the lock before the door is hung and the trim is nailed. Four things are set at that stage and are expensive to change after paint: the bore and backset of the door, the thickness of the door, the hardware finish on every other door, and where the nearest Wi-Fi or hub sits. Order the lock two to three weeks before trim-out; install it after paint, in the same visit as the rest of the door hardware.
Exterior doors sit in the middle of the whole-house sequence: the slab and jamb go in while the house is still rough, the casing goes on with the rest of the trim, and the paint comes after. Everything the lock needs from the door is fixed at the first step. The lock itself arrives at the last.
What the door decides for you
| Door detail | Standard | Why it matters for a smart lock |
|---|---|---|
| Cross bore (the big hole) | 2 1/8 in | Nearly every smart deadbolt expects it; a 1 1/2 in bore on an older door needs a hole saw and a steady hand |
| Backset | 2 3/8 in or 2 3/4 in | Most locks ship an adjustable latch; a few keypad models are 2 3/8 in only |
| Door thickness | 1 3/8 in to 1 3/4 in | Thicker doors (solid slab, 2 1/4 in) need a thick-door kit ordered separately, often a two-week wait |
| Bore spacing (deadbolt to handle) | 5 1/2 in | Matters only for one-piece handle-plus-deadbolt sets; standalone deadbolts do not care |
| Strike and jamb | 1 in throw, wood or steel jamb | A bolt that drags on the strike will make an auto-lock fail every night; the jamb is where the fix lives |
If you are replacing the slab, ask for a factory bore to the standard above and say which lock is going in. If you are keeping an old door, measure those four numbers now, before the painters arrive; a door that needs a fresh bore is far easier to cut and prime while it is off its hinges.
Retrofit or full replacement
There are two families, and the choice changes what you order and what your locksmith does.
- Retrofit (inside only). The motor replaces the thumb-turn on the inside and the existing deadbolt and key stay. Nothing changes on the outside of the door, which is the right answer when the exterior hardware was chosen to match the house. Typical price $130 to $250.
- Full replacement. The whole deadbolt goes, and you get a keypad, a fingerprint reader or a keyway on the outside. This is the option to pick during a renovation, because the finish is chosen at the same time as the rest of the door hardware. Typical price $150 to $350; models with a fingerprint reader and a camera sit at the top of that range.
Power and connectivity, in plain terms
| Choice | What you get | Trade |
|---|---|---|
| Bluetooth only | Unlock from the porch with your phone | No remote access; fine for a back door |
| Wi-Fi built in | Remote unlock, codes for the cleaner, delivery windows | Battery life of 2 to 6 months; the router must reach the door |
| Bluetooth plus a Wi-Fi bridge | Same as above with a plug-in bridge inside | One more device, but batteries last a year |
| Zigbee, Z-Wave, Thread or Matter | Works with the hub you already run | Only worth it if the hub exists; otherwise choose Wi-Fi |
The renovation angle is the router. A front door at the far end of a new addition, behind new drywall and a steel door, may be out of range of the router that used to reach it. Test the signal at the door before the walls close; a mesh node or an outlet near the door costs almost nothing while the electrician is on site and a lot after.
Finish matching and lead times
Interior levers, hinges, the exterior handle set and the smart lock are all visible on one door. Smart locks come in fewer finishes than passage hardware, usually satin nickel, matte black, bronze and brass, so pick the lock first and match the rest to it, not the other way around. Stock finishes ship in days. Anything ordered as a set with a matching handle, a thick-door kit or a colour that is not the default runs two to four weeks, which is why the lock goes on the order list with the doors and not with the paint. The ordering timeline puts door hardware in the same window as interior doors.
If you are choosing a full-replacement keypad or fingerprint lock, a purpose-built maker such as Lockin lists the bore, backset and thickness range on every product page; check them against the table above before you add to cart.
Install after paint, not before
- Do not install the lock before the painters. Overspray in the keypad and tape on a fingerprint reader are the two most common warranty calls. Hang a blank deadbolt or a construction lock through paint, then swap.
- Check the bolt throws freely with the door closed. Auto-lock needs a bolt that slides into the strike without lifting the door. If it drags, adjust the strike plate; do not tell the lock to try harder.
- Set codes on the day the contractor's key retires. A lock with a temporary crew code is the tidy way to end a renovation: delete one code and the house is yours again.
A smart lock usually does not need a permit, but a new exterior door or a wider opening can; the permit guide has the trigger list.