Why your Smoke Alarm Keeps Going off at Night - With Fixes

Written by Jason Hutchinson
4 Min read

Do your fire and smoke alarms keep you awake at night?

We've all been there before, the early hours of the morning and time to get up and ready for work soon, until the shrill scream of your smoke alarm goes crazy for no reason, filling you with panic staring at the ceiling and wondering why you've been woken up from a false alarm. Here we can go over how these smoke alarms work, all the common reasons that they randomly go off, and how to fix them too.

How do smoke alarms work?

Having a little bit of an understanding of how this bit of tech works will help to push you in the right direction when they aren't working. Alarms will fall into one of two categories to detect smoke, ionisation and photoelectric.

Photoelectric alarms work by having a beam of light inside of them to detect smoke alarms. When anything gets in the way and the beam of light is fractured, then the alarm will go off.

Ionisation alarms work a little bit differently, they have ions and electrons buzzing around inside of them, and when smoke makes its way in, the smoke particles cling to the ions. This changes the chemical structure and triggers the alarm, but there are other things than smoke that can affect the light beam or cling to the ions, so this is why they can go off randomly.

Causes of smoke alarms going off

There are quite a few things that can affect these two types of smoke alarms, the majority of which are preventable so let's have a look through them.

Burnt Food

Absolutely everyone burns food now and then, and burning food creates smoke. To stop this from interfering with your alarms when you don't want it to, look into vents or extractor fans, or maybe move the alarm a little bit away from your oven, stove, etc.


It's really important to have smoke alarms everywhere, in most rooms, hallways, fireplaces and around the kitchen, but the actual placing of them has to be specific too. Some things that could be interfering with the smoke detector could be if it's close to a shower and the steam is affecting it, or maybe it's directly above a toaster and so some smoke off of that is affecting it. Just have a little look at what's surrounding the alarm and see if any outside elements are causing it to go off sometimes.


Whilst it is a pretty disgusting thing to have to do, you might have to investigate inside the smoke alarm to see if any little insects, bugs or other critters have made their way into the inside of the device and are becoming a problem for it.


In a similar way to how the smoke from burned food can be a problem for the detector, the steam from things like showers can also be a problem. Check if alarms are too close to windows, doors and showers that get steamy, and if they're going off randomly then maybe invest in a fan or vent to pull the steam away from the detector. This could also be a problem with the sensitivity of the alarm.


Dust particles can get in the same way that insects can, and they can cause the alarms to go off. Taking it apart just a little bit and having a clean is always a good idea to prevent any kind of build-up from being an issue. Cleaning them just once a year with a vacuum brush should be enough to keep them in good condition.


You should probably be changing your smoke alarm batteries every six months with just your average batteries. A nice way to remember to do this is to change the batteries whenever the clocks go forward. Usually, though, you'll get a slightly different sound when the alarm is out of battery, a little beep that might be prolonged or just every few minutes to keep reminding you that it needs to be changed.


It's not a very common thing, but malfunctions can still happen with smoke alarms. Most modern ones will have some kind of little light on them to indicate that it's got something wrong with it, so just make sure to be checking it on regular basis. Most of the time this will mean you will need to get a new smoke alarm.

End of Life

Smoke detectors will tell you when they're at the end of their life pretty well, they'll let you know with a little beep and it'll probably be time for a new one.

Ways to adjust your smoke detector

You can make little adjustments to your smoke detector so that it works just the way that you want it to, so have a little play around with it so it's not annoying and you feel safe.

Placing them

All the key areas are the hallways, bathrooms, kitchens, stairways and any other fire hazards. It's also important to try to keep things around ten metres away from things that will interfere with it like kitchen appliances, showers, doors, etc.

Checking battery life

Replace the batteries every six months so that you're always on top of it and you know you're safe, and if it's one of the new smart metres, check the connection on a regular basis, especially if you're getting false alarms.

Adjusting the sensitivity

This is something that should only be done with professional help and the guidance of someone who knows what they're talking about to ensure your safety, but if there are problems with the alarms sensitivity and it's picking things up too easily then that can be altered.

Smart smoke detector

These clever little devices give you a lot more control over your house and your safety, everything can be managed and checked from your phone!

Smoke alarms are an essential part of your safety and feeling secure in your own home, so make sure that you keep them fully working all the time! Change the batteries every six months and check for faults so that you don't get any problems.

Appliances made simple. 

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