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🔐 Device Guide

Retrofit or Replace — Which Smart Lock Install Is Yours

Published October 2026 · Last verified October 2026

Retrofit vs replacementTwo ways a lock goes on a doorRetrofit• Keeps your key• Mounts inside only• Reversible, renter-safe• About fifteen minutesFull replacement• New keys and keypad• Whole deadbolt swapped• Permanent change• About an hourPick by whether you rent and whether you want an outside keypad.Illustration — a schematic; details vary by device and setup.
Pick by whether you rent and whether you want an outside keypad.
Measure before you buyThree numbers for a replacement1Backset2Door thickness3Bore hole4Confirm fitConfirm the door is standard before ordering a replacement lock.Illustration — a schematic; details vary by device and setup.
Confirm the door is standard before ordering a replacement lock.

A smart lock goes on your door one of two ways: a retrofit that keeps your deadbolt and key, or a full replacement. Here is how to tell which install is right for your door.

Bill Davis
Bill's Home Tech · Atwater, Ohio
Want the full deep-dive?
Download the printable Retrofit or Replace guide
PDF · plain English · no ads · made by Bill
Topic
Retrofit vs replace
Category
locks
Best for
DIY & renters
Typical Price
$150 – $300

A smart lock goes on your door one of two ways: a retrofit that keeps your deadbolt and key, or a full replacement. Here is how to tell which install is right for your door.

What's inside this guide

The printable PDF walks through 23 short chapters, in plain language. It also includes an everyday cheat sheet, a plain-English word list and at-a-glance pictures.

  1. The two install styles, plainly
  2. Retrofit: keep your deadbolt and key
  3. Replacement: a whole new deadbolt
  4. The quick way to tell which is yours
  5. Renters: why retrofit usually wins
  6. Owners: when replacement makes sense
  7. Keeping your existing key
  8. Meet the retrofit locks
  9. Meet the replacement locks
  10. Measuring your door: three numbers
  11. Backset: edge to the bolt center
  12. Door thickness and the bore hole
  13. Tools you will need
  14. How long it really takes
  15. Installing a retrofit, step by step
  16. Installing a replacement, step by step
  17. The strike plate and alignment
  18. What can go wrong
  19. Ohio winters and your door
  20. Finishing up and the first codes
  21. When to DIY and when to call a pro
  22. Older and nonstandard doors
  23. When to Call Bill

Get the printable guide

Everything above is a quick summary. The full, printable guide — the same words, laid out to read and keep by the computer — is a free PDF.

Download the printable PDF →

Last verified October 2026. Information accurate as of October 25, 2026.

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✍️ Every guide researched, written, and reviewed by Bill — your local Portage County tech.

Any prices or outside products mentioned in this guide can change over time — the details here were last checked August 2026 and this page is accurate as of October 18, 2026; please confirm current pricing before you buy. See how often we review our guides →