5 Reasons for Smoke Detector Red Light

Smoke detectors come with different brands such as Kiddo and First Alert. They act slightly differently. However, the difference between them might not be too far apart especially when it comes to what different colours of blinking light signify.

You might be having some thoughts about your smoke detector red light flashes, probably you feel it should blink a red light when there is a smoke or fire emergency. But then, you can’t wrap your head around why your smoke detector red light keeps blinking.

If you are looking for answers to this, you are at the right place.

Below I will be breaking down every possible thing that a smoke detector red light signifies when it blinks.

5 reasons for smoke detector red light Flashes

Before I proceed to the reasons why you are stuck figuring out what the red light on your smoke detector means. There is something you have to put in mind. 

Most smoke detector brands have outlined what different light signifies and how you can decipher what a certain type of blinking means based on its user manual.

However, these might not differ across common brands of smoke detectors. 

That being said, I will be breaking down some common reasons why your smoke detector is blinking red light

1. The batteries are Low batteries 

the batteries are low
Source: expresselectricalservices.com

The shelf life of your smoke detector battery is 10-12 months. If you have a low battery you could experience a red light flashing on your smoke detector. However, not all smoke detector signifies low battery with a red light, some signifies it with a yellow flashing light, however, if you are using brands like First Alert smoke detectors, it shouldn’t come as a surprise to you that it flashes a red light for low battery

A good pointer to easily figure this out is the time gap between each flash. For low batteries, the time gap between each flash is usually 20-30 seconds.

If your batteries are Low, here is how you can replace them

  • Remove the battery compartment cover
  • Now, slide open the tray and take out the old batteries.
  • Avoid touching any of the electrical contacts inside the battery compartment while doing this
  • Finally, insert the new set of batteries just as the old ones were placed

NOTE: It is advised to change the smoke detector battery once every year

If you are looking for a good pointer to determine if your battery is low you should check here.

2. The Smoke Detector Alarm is working

Just as discussed earlier, a green light signifies that the smoke detector is working properly or the alarm is functioning, while in some other brands of smoke detectors it signifies a red light. 

You might not easily figure this out, however, one good pointer is the time gap between each smoke detector red light blink.

As long as you are not perceiving any brunt smell or smoke and the alarm isn’t ringing there is no need to panic.

3. The Smoke Detector is Almost expired

the smoke detector is almost expired

Usually, a smoke detector has a shelf life of 10 years. So you don’t need to worry about a replacement for a decade, However as the end of its shelf life comes close, the smoke detector will begin to malfunction and some of the things you might notice are the battery dying too quickly coupled with excessive blinking of the red light, which could mean anything aside from an emergency.

However, when it continues like this, it could make you less receptive when you are faced with a real emergency since the red flashing light becomes a new normal.

That being said, a good rule of thumb is to replace it A month or a few months before it expires to be on the safer side.

3. There is too much Dust  

Apart from detecting smoke or burnt smell, you could be faced with your smoke detector red light blinking when it detects dust. 

When there is too much dust in your environment, the smoke detector gets dirty over time and as a result, it can affect your smoke detector capability when it gets too frequent.

If you have replaced the battery and it’s been a long time since you install the smoke detector but you can still see a smoke detector red light. Try cleaning your smoke detector.

Here is how to do that

  • Remove the chamber from the smoke detector.
  • Next, use a lint-free cloth to wipe the chambers 
  • Next, use a vacuum to blow out any dust/dirt in your smoke detector

5. Smoke has been Detected

smoke has been detected

If your smoke detector is blinking a red light very rapidly and the alarm sound is also visible, it is a red flag and it signifies that smoke has been detected

If you are faced with a scenario such as that, you should move out of the house immediately and ensure everyone is out the door before calling security operatives.

Probably, you might be courageous enough to go inside and figure out where the smoke or fire is coming from, but you should do that cautiously.

How to Turn off Red light on Smoke detector

If your smoke detector has been blinking red light for a while without coming to a halt, maybe it is close to its expiry date. 

If you are faced with that, you can simply follow these steps below to shut stop the red light 

  1. Take out the batteries.
  2. Long press the silence button for 15 seconds till the beeping stops
  3. Now insert the battery again provided the battery is not low.
  4. If this doesn’t stop it, reset your smoke detector

Smoke alarm red light flashing every 10 seconds

If you are faced with your smoke detector red light flashing its light after every 10 seconds. It is doing that as the after effect of a recent smoke outburst. So the 10 seconds blinking signifies that it is in a desensitized state.

Red light flashing on smoke detector after changing battery

Once you change the batteries of your smoke detector, it should clear out any error on the smoke detector and it is a normal scene. But if it persists for too long, you should carry out a reset on the smoke detector. 

You might experience this with electrical-powered smoke alarms using a battery backup.

Smoke Detector Green light

Smoke Detector Green light

Depending on the brand, a green light that the batteries are low or a unit in a series of interconnected alarms is blinking and an alarm has been triggered. To better understand your smoke detector, you should endeavour to read through the user manual that comes with it.

How to Reset the Smoke Detector?

Before you reset your Smoke detector you have to do some checking to it to ensure you are approaching the right problem with the right solution. That said, here is how you can reset your smoke detector.

NB: The test instruction is always on the user manual since the reset procedure slightly varies based on the brand

That said, here is how you reset your smoke detector

  • Locate the test button
  • Push and hold the button on your device for around 5 seconds till you hear a beep sound. In some instances, you will hear a series of beeps.

If your smoke detector is always beeping and chirping check here for a comprehensive guide to resolve that.

What does a Yellow Light Mean?

Some smoke detector gives out a green light while some give out a red light in almost every scenario, however for some a yellow light usually mean that your smoke detector battery is low and needs a replacement. While in some other cases, it could mean that the device is reaching the end of its life and needs a replacement.

Smoke detector red light with no sound

There is no cause for alarm if your smoke detector is giving out a red light since it simply means the detector is receiving power. it is common with hard-wired smoke detectors.

Why is my smoke detector red light flashing every 20 seconds?

The most common reason why your smoke detector is blinking every 20 seconds is due to low battery. However, not all smoke detectors signify a low battery with red lights, some do it with yellow lights or green lights depending on the smoke detector brand.


By now, you should have figured out the reasons behind your smoke detector red light and the different things you can do to stop the red light. 

If your smoke detector red light keeps flashing and it becomes frequent without the presence of smoke or burnt smell, then the smoke detector is closing in on its shelf life and needs to be replaced.

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