How to Install Smoke Alarms in Your Home

I’d like to add some extra smoke detectors to my home, but I want to make sure they’re reliable. Do I need to have them hardwired? – Amy from Ohio

Smoke alarms are one of the best safety features you can buy for your home and can be purchased for as little as $7. While smoke detectors are hardwired into houses in new construction, battery powered unit are best for existing homes. They are easy to install, but you need to remember to change the batteries about twice a year. Install at least one smoke alarm per level of your home near the bedrooms, and another in the garage.


  1. Danny:

    I have an older nutone hardwired smoke detector that is buzzing or humming. This has just started and I’d like to know if you have any suggestions on what could cause this and any possible fixes. The detectors were installed with the house in 1975. Nutone Model S180.

    Thanks for any help

  2. Ann-
    Smoke detectors should be replaced every 10 years as the sensor inside of them becomes unreliable after this length of time. Consult a licensed electrician about replacement.

    Smoke detectors should not be installed in a garage; due to false alarms. A heat detector is the better choice, following the manufacturers instructions.

  3. Wow, I have the same pair of these in my house (Nutone Scovill S180 hardwired smoke detectors). I have been looking for a replacement path to keep the interlink and A/C functionality, but so far no luck.

    I would prefer not to take apart the wiring. Seems like every manufacturer has their own idea of what the plug should be. They all should be taken out and beaten for not standardizing this with the ISO, NEMA, or another similar organization.

    Anyone find a migration path?

  4. We have 3 hard-wired Lifesaver 1255 Smoke Detectors that have been in our home since 1990- actually removed from place because they kept going off every time I cooked- I know, not a smart move- but there has to be a better product on the market. I would now like to replace them. The wiring and base plates are still in place on all 3 floors. Can you suggest an appropriate brand that may be compatable with the hard wiring I already have? If possible I would like to combine a CO2 detector with this.

  5. 6/26/11
    I have 4 of the Nutone Scovill S-180L hard wired (4 wire) smoke detectors in my home. I too have been looking for replacements with no luck. Any imfo would be appreciated.
    Cleaning the filters and blowing the dust out does stop them from going off without cause.

  6. I was asked by L&I to install hard wired smoke alarms at my business since I live above my upholstery shop . well I went on and did the work on my own since I have experience in electricity . I would like to know if I need a permit .ccertification

  7. Where should I install Smoke Detectors in my home and should I put one in my garage. I have a 3 Bed room house with an Open Kitchen, Living Area and a Large Den. I would appreciate your response and thank you for your consideration.


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