Ask Our Experts: Whole-Home, Wired Smoke Detectors

May 16, 2016 | 5:33 pm
Smoke detectors save lives!
Smoke detectors save lives!

Question for Our Experts:

I’ve heard about whole-home, wired smoke detectors.  What are they all about, and why are they so great?

Our Experts’ Answer:

Short Answer

This type of smoke detector is called “wired” because it relies on a hardwired power connection as its primary source of power (with battery as a backup), and it’s called “whole-home” because it generally communicates with the other smoke detectors throughout the home (i.e. if one goes off, so do all the others).  Both provisions make the home much safer and allow occupants to respond to fires faster.

Detailed Answer

First and foremost, remember that any working smoke alarm is better than no working smoke alarm.  Safety first!

Now, a quick overview of traditional battery-only smoke alarms vs. hardwired smoke alarms:


  • Battery-only smoke alarms rely solely on batteries for their power, and they are generally not communicating devices (i.e. they’re not “tied together” so that if one goes off, others go off as well).
  • Given that information, imagine this scenario: you have one battery-only smoke alarm in your basement, one on the first floor, and one of the second floor.  A fire starts in the basement, and you’re on the second floor.  The odds are that you’ll smell smoke before you hear the alarm, if you’re lucky.  If you’re sleeping, these odds worsen drastically as the house fills with smoke.  With non-communicating, battery-only smoke alarms, you’re relying on the rising smoke to set off each alarm as the smoke gets to it.  By the time the second-floor alarm goes off, the basement and first floor could be fully engulfed in flames, blocking your primary escape routes.
  • When the battery dies, the alarm will start to chirp (to prompt you to replace the battery).  Many people remove the battery to stop the chirping – but then they forget to replace the battery with a new one.  This is rolling the dice for disaster, as battery-only smoke alarms have no other source of power and will not operate if they don’t have a functioning battery installed.


  • Like battery-only smoke alarms, hard-wired smoke alarms have batteries as a power source.  However, they also have a hard-wired power connection to provide power as well.  In this scenario, two sources of power are better than one.  Additionally, many hard-wired alarms also communicate with each other.  If the basement alarm goes off, the second-floor alarm will also go off – just because the basement alarm is going off.
  • Given that information, re-imagine the scenario above: you have hard-wired smoke alarms in your home – one in the basement, one on the first floor, and one on the second floor.  A fire starts in the basement, and you’re on the second floor.  When the basement alarm goes off, EVERY smoke alarm in the house goes off, alerting everyone in the home instantly.  This gives everyone much more time to respond appropriately.
  • When the battery dies, the alarm will start to chirp (just like battery-only smoke alarms).  With hardwired alarms, however, your alarm should still work (even with no battery installed) as long as the electric is on.  In this scenario, the battery is a backup, not the main power source.  Of course, you should still promptly replace the dead battery after removing it – never leave a smoke alarm without a functioning battery installed.

Given this information, you won’t be surprised that, in our area, current codes for new construction generally require: 1 smoke alarm in the basement near the heating source (recommended carbon monoxide/smoke alarm here), 1 at the top of each set of steps, 1 in the kitchen, 1 in each bedroom and, if there’s a second floor hall leading to the bedrooms, 1 there as well. All need to be placed on the ceiling or on the wall within 12” of the ceiling (because smoke rises rapidly) and ALL MUST BE HARDWIRED WITH A BATTERY BACKUP.

For professional assistance with this and other home maintenance work, Tuckey is the local expert to call. Keep our number handy – you never know when you might need us! Call (717) 249-3733 or visit for more information.

[Photo By Tumi-1983 (Own work) [GFDL ( or CC BY-SA 3.0 (], via Wikimedia Commons]

DISCLAIMER: This article is provided as a reference guide only. A qualified, professional contractor like the Tuckey Companies should handle all interior design, mechanical, electrical, plumbing, remodeling, metal fabrication, and restoration projects. Information presented here is of a general nature that may not be applicable in all situations. Tips, articles, and accompanying information do not represent an official recommendation of the Tuckey Companies.

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