How do Smoke and Fire Alarms work?

We’ve all have a fire alarm in our homes, but have you stopped to wonder how they work? Or maybe you’re looking to buy a new one and don’t know the first thing about it.

Read on so you’ll have everything you need to know about smoke and fire alarms. First, let’s get into the types of smoke alarms.


This is the kind of smoke alarm that you can connect with the electrical system of your house. These models usually come with a backup battery so they’ll keep working during a power outage.

If you live in an area where power outages happen pretty regularly, this is the safest option to go for. They would be extremely reliable in the event of your power going out.

The main downside is that it can be a pain to install sometimes.


Based on the name, you can assume that this is the kind of smoke alarm that doesn’t just detect fire. Most of them keep the level of carbon monoxide in your home in check as well.

They serve a dual purpose and they come in a variety of options like hardwired, battery-operated, or smart.

You can just easily choose one that fits your budget the best.


This is one of the latest innovations in home tech. You will also receive warnings on your smartphone if the alarm goes off.

Smart alarms also have the ability to communicate with other alarms you have set up in your home, so you’ll be able to pinpoint where the smoke is coming from.

For this kind of safety, you’ll have a pay quite the pretty penny. But it’s well worth because safety should always be on top of the list of your priorities.

What kind of sensors are in these alarms?


These sensors are able to detect large flames - meaning, faster burning fires. This is extremely useful because large flames don’t produce much smoke, making them harder to detect.

This sensor is basically a small amount of radioactive material and two metal plates. This setup ionizes the air.

When a fire occurs, the smokes should pass through the device and this interrupts in the ionization. This will then make the alarm go off.


These sensors are better at detecting smoldering fires (barely burning) because these generate a lot more smoke.

As its name implies, it keeps detects fire through the absence of light (because of smoke).


These sensors are your safest bet because they include both ionization and photoelectric sensors. Obviously, the best kind of smoke alarm you should get must have a dual sensor to protect you from both smoldering and flaming fires. 

Dec 30th 2018

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