The Smart Lock Will Not Fix a Bad Door
You bought a $250 Yale Assure Lock 2. You open the box, read the instructions, and discover your door is 1-3/8 inches thick and the lock needs 1-3/4 inches. Or your deadbolt hole is drilled off-center and the bolt scrapes every time it extends. Or your Wi-Fi does not reach the front hall.
These are not smart lock problems. They are door problems. And they are the reason 40% of smart lock returns are not defective — they just do not fit.
Check these five things before you order. Each one takes two minutes.
1. Door Thickness and Backset
What to measure: The thickness of your door slab (edge to edge) and the backset (distance from the door edge to the center of the bore hole).
| Measurement | Standard | What Smart Locks Need |
|---|---|---|
| Door thickness | 1-3/8" (interior) or 1-3/4" (exterior) | Most support 1-3/8" to 2-1/4" |
| Backset | 2-3/8" or 2-3/4" | Both are standard — most locks include both |
The problem: Some older doors or custom doors are 1-3/8" exterior grade. Many smart locks — especially the premium ones — are designed for 1-3/4" doors and need an adapter kit for thinner doors. Check the product specs before buying.
How to measure: Tape measure, edge to edge for thickness. For backset, measure from the door edge to the center of the deadbolt keyhole.
If your door is thinner than 1-3/8": You need a lock specifically rated for thin doors. The August Wi-Fi Smart Lock (4th gen) and the Switchbot Lock are two of the few that handle doors down to 1-1/4".
2. Deadbolt Bore Hole Condition
Your door needs a cross bore (the large hole, usually 2-1/8 inch diameter, where the deadbolt thumb turn sits) and an edge bore (the smaller hole on the door edge where the bolt extends).
What to check:
- Cross bore diameter: Should be 2-1/8 inches. If it is 2-1/4, most smart locks still fit — but check. If it is smaller than 2-1/8, you need to ream it out with a hole saw.
- Edge bore alignment: The edge bore must be perfectly aligned with the cross bore. If the bolt sticks or scrapes when you turn it now, a smart lock motor will struggle or fail to extend the bolt fully.
- Strike plate position: The deadbolt should extend fully into the strike plate hole in the door frame with no resistance. If it barely catches or you have to push the door to engage it, the strike plate needs adjusting — not the lock.
Test: With the door open, extend the deadbolt. It should move smoothly with no scraping, sticking, or grinding. If it does not, fix the mechanical issue first. A smart lock motor cannot overcome a misaligned bolt — it will burn out trying.
3. Wi-Fi or Bluetooth Signal at the Door
This is the most overlooked check. Smart locks need connectivity for remote locking, guest codes, and activity logs.
| Connection Type | Range | What It Means |
|---|---|---|
| Bluetooth only | ~30 feet | Phone must be nearby; no remote access |
| Wi-Fi (built-in) | Router range | Remote access anywhere, but needs strong signal |
| Wi-Fi (via hub/bridge) | Hub range | Hub connects to Wi-Fi; lock talks to hub via Bluetooth or Z-Wave |
How to test Wi-Fi at your door: Stand at your front door with your phone. Check the Wi-Fi signal strength. If you have one bar or the connection drops, you need a Wi-Fi extender before installing a Wi-Fi lock.
Which locks need what:
- August / Aqara: Bluetooth primary, Wi-Fi via included Connect hub — hub placement matters more than door Wi-Fi
- Nest Yale: Wi-Fi built-in — needs good signal at the door
- Schlage Encode: Wi-Fi built-in — needs good signal at the door
- Kwikset Halo: Wi-Fi built-in — needs good signal at the door
- Switchbot: Bluetooth + hub — hub range is the limit
If Wi-Fi is weak: A $25 Wi-Fi extender placed halfway between your router and the door solves this. Do not buy a $300 lock and then run it on one bar.
4. Smart Home Compatibility
If you already use a smart home system, your lock needs to work with it. If you do not, skip this — but think about whether you might add one later.
| Lock | Alexa | Google Home | Apple HomeKit | SmartThings | Matter |
|---|---|---|---|---|---|
| August 4th gen | Yes | Yes | Yes | Yes | Yes |
| Nest Yale | Yes | Yes | No | Partial | No |
| Schlage Encode Plus | Yes | Yes | Yes | Yes | Yes |
| Kwikset Halo | Yes | Yes | No | No | No |
| Aqara U200 | Yes | Yes | Yes | Yes | Yes |
| Eufy S230 | Yes | No | Yes | No | No |
Why it matters: If you have Apple HomeKit and buy a Kwikset Halo, you cannot control the lock from the Home app or use Siri. You will need the Kwikset app separately — which works, but defeats the purpose of a unified smart home.
Matter support is the future standard that works across all platforms. If you are buying new, prioritize a Matter-compatible lock.
5. The Latch Alignment Problem
This is the silent killer of smart lock installs. Your existing deadbolt works fine by hand because you subconsciously push or pull the door while turning it. The smart lock motor cannot do that — it just drives the bolt. If the bolt and strike plate are even slightly misaligned, the motor strains, the bolt does not fully extend, and the lock reports “locked” when it is not.
How to check: Close the door. Try to extend the deadbolt without pushing or pulling the door. If it resists, scrapes, or does not go all the way in, you have an alignment problem.
How to fix:
- Adjust the strike plate. Loosen the screws, shift it slightly up or down to align with the bolt, and retighten. Sometimes 1/16 inch of movement is enough.
- Enlarge the strike plate hole. Use a round file or a Dremel to widen the hole slightly. This gives the bolt clearance even if alignment is not perfect.
- Shim the hinges. If the door sags (common with heavy doors), the bolt drops below the strike plate. Remove a hinge pin, lay it on a hard surface, and give it a gentle bend with a hammer — this tilts the door back up. Or add a hinge shim behind the bottom hinge.
Fix this before you install the smart lock. It takes 10 minutes and prevents the most common support call.
Quick Decision Guide
| Your Situation | Best Lock |
|---|---|
| Standard 1-3/4" door, good Wi-Fi, no smart home | Schlage Encode Plus — simple, reliable, Matter |
| Thin door (1-3/8"), any smart home | August 4th gen — fits thin doors, works with everything |
| Apple HomeKit user | Aqara U200 or Schlage Encode Plus (Matter) |
| Budget, basic needs | Amazon Smart Lock — $130, Alexa only |
| Renter, cannot replace deadbolt | Switchbot Lock — goes over existing thumb turn |
| Want keypad + app | Schlage Encode Plus or Yale Assure Lock 2 |
One More Thing: Check the Door Frame
A smart lock is only as strong as the door frame it bolts into. If your frame is rotting, cracked, or secured with short screws (less than 1 inch), a kick will break the frame before the lock fails.
Fix: Replace the strike plate screws with 3-inch deck screws that reach into the wall stud behind the frame. This costs $2 and takes 2 minutes, and it makes the deadbolt 10x more resistant to forced entry. Do this regardless of whether you install a smart lock.