Replacing a hardwired smoke alarm is a piece of cake. If you purchase a smoke alarm from the same manufacturer, you might be able to use the same wiring harness. You simply disconnect the existing smoke alarm and pop in the new one. The clip below shows me doing this. You can do this too.

To be safe, turn the power off first, of course.

If you can't find the same unit, consider purchasing a wiring adapter, which converts the wiring harness from one manufacturer to another.

With an adapter, there's no wiring that needs to be done. You just pop the old harness out of your smoke alarm and plug it into the adapter. From there, you plug the adapter into your new smoke alarm. It's just like I showed in the clip above. You'll probably need to replace the mounting ring, which consists of two simple screws. It's about as easy as replacing a cover plate on a light switch. Anyone can do this.

The most difficult way to replace a hard-wired smoke alarm is to actually re-do the wiring. Even then, however, it's not difficult. It's a matter of simply swapping out the wiring harness. To make proper electrical connections, check out the advice given by The Family Handyman: https://www.familyhandyman.com/electrical/wiring/how-to-make-safe-wire-nut-connections/. Also, here's a video they put together showing the steps:

If you can do this, you can replace a hardwired smoke alarm. The steps are pretty simple:

Here's a video with the boring parts sped up to show what these steps look like: https://youtu.be/RWIL10XXDFU

Disclaimer: as with all electrical work, don't do anything that you're not qualified to do. Don't take this as a complete electrical how-to guide, either. This is just an overview. The installation instructions from the manufacturer are a heck of a lot longer than this and are packed with disclaimers. You should read and follow all of those instructions, because more steps will surely be required, depending on the specific unit.

Author: Reuben Saltzman, Structure Tech Home Inspections

Reuben Saltzman is a second-generation home inspector with a passion for his work. Naturally, this blog is all about home inspections and home-related topics in the Twin Cities metro area. In addition to working at Structure Tech, he is also a licensed Truth-In-Sale of Housing Evaluator in Minneapolis, Saint Paul and several other cities.

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