Ultimate Smoke Detectors Buying Guide

Regardless of how big or small your house is, a smoke detector is an inevitable device for your building.
We never know when a mishap can happen, and accidents are always around the corner.

File:Smoke detector.JPG - Wikimedia Commons
Smoke Detector Guide

There is more than one way a fire can break out, or harmful smoke is around, so we should take all the preventive measures to ensure that our loved ones and valuable belongings are kept safe, and smoke detectors are one of them.
However, having a random smoke alarm is just not enough.

You got to get a good one that is up and working to warn you in time if a fire goes out.
Here, we will help you select the right product as we talk you through smoke detector types, how they work, and what you should consider when choosing one.

Types of Smoke Detectors 

There are currently three types of smoke detectors available in the market, namely the ionization, photoelectric, and combined smoke detector.

1. Ionization Smoke Detectors

The ionization smoke alarm is the one that comes with a slight amount of radioactive material.

The radiation is set to pass through a chamber that ionizes, filled with air that separates the two electrodes.

A small current constantly moves between the electrodes, and as the smoke enters the alarm, the alpha particles will absorb it.

It will lead to the alarm going off as the current will be interrupted. These types of alarms work the best for abrupt and rapidly spreading fires.

2. Photoelectric Smoke Detectors

The photoelectric smoke detectors are a cheaper solution and work with the help of a light source.

A light beam collimating setup operates along with a photoelectric sensor.

As the smoke passes through the optical chamber, the path of the light beam is disturbed.

Therefore, as the light strikes, the sensor sets off the alarm. These alarms are best suited to detect slow, smoldering fire.

3. Combined 

The smoke alarm, which is labeled as a combination of both, comes with two technologies.

One is photoelectric, and the other is ionization. As listed, the former best respond to fast-raging fires while the latter is better used in slow smoldering fires.

For the best protection of your home or office, it is recommended that you must use both as one never knows how a fire will start off and at what rate it will spread.

So, you can have a single detector that possesses both technologies rather than getting two separate alarms.

Smoke Detectors Working Principle

The smoke alarm works on certain principles, defined by the type of alarm you choose.

Above, we have listed the types and a bit about their working, but here is a thorough detail of the smoke detector working principle according to their technology.

1.Optical or Photoelectric Technology

These optical detectors are screwed at the ceiling because smoke heads towards the top of the room.

The gases generated with fire are hot and less dense, so they rise upwards.

The alarms have an opening from where the smoke passes into them.

The detectors contain a light-emitting source and a photoelectric detector (light detector), along with a circuit and a fire alarm.

Usually, the light emitted from the source does not reach the light detector because it has been set so that the beam does not fall directly onto it.

However, smoke passes through the opening and enters the chamber; the light beam is scattered because of the smoke particles.

Ultimately, it falls onto the light detector, sending a signal to the circuit fitted into the smoke alarm.

As the circuit receives the signal from the light detector, it ultimately senses that something is wrong as the smoke has come into the sensor and, therefore, sets off the alarm to wake you up and save your life.

2. Ionization Technology

The ionization technology works differently as compared to the optical alarms.

These operate with the help of radioactive material.

There are two electrodes between which you have the positively and negatively charged ions moving around among the two electrodes.

Apart from that, there is an opening, a circuit, and an alarm.

In normal conditions, the radioactive material emits alpha particles, positively and negatively charged ions.

These flow back and forth between the electrodes, assuring that the current is appropriate and that there’s no problem.

But when the fire goes off and smoke enters the chamber, it gets mixed with the ions.

Therefore, they disturb their movement and slow down the charge, making them less efficient.

Now, as their collision with electrodes is disturbed, the circuit inside such alarms suddenly detects the change.

That way, it gets to know something is wrong, and ultimately the circuit sends the signal to an alarm which would start ringing and telling you there is a fire around.

The alarm will shut down as soon as the smoke clears and particles are back at their initial place, i.e., a smooth collision between the electrodes.

How to Choose a Smoke Detector?

So, now you know the smoke detector types and their working principle, the next question is that how you pick one?

Here is the list of 5 necessary considerations you should always keep in your mind while buying a Smoke Detector.

1. Standard Certification

When looking for smoke detectors, always take a peek at their certification.

Wherever you are living, the authorities have specific standards.

Some of them are acceptable around the globe, while others are exclusive to a particular state.
So, watch out for the standard certifications and make sure that you get a certified alarm.

2. Battery Life

The battery life of a smoke alarm matters a lot.
Many homes catch fire because they have a smoke alarm with a battery gone flat a long time ago.

So, always look for those that come with a decent battery and can be used for at least 5 to 10 years.
Even if you plan to get the alarms powered from your house’s main circuit, they do have a backup battery in case your home’s circuit fails to provide power to it.

3. Test Button

For any smoke alarm, a test button is necessary.
It helps you in determining how it will sound and whether it is loud enough or not.
Some of the alarms can be tested with the help of remotes, while others may be going off as you shine a torch on them.
For the rest, you’ll have to climb up a ladder and reach with a broom.

4. Silent Button

As the alarm goes off, there are cases when the mishap would be slight, or it might be deliberate.

So, in that case, you need to have a mute button using which you can turn it off or at least shut it down momentarily.

5. Expiry Date

And lastly, don’t forget to check the expiry date on the alarm.
Some may be there to last for a long time, maybe a lifetime, but getting to know about the date it is guaranteed to work at its best is always good.


Which is better ionization or photoelectric smoke detector?

Ionization smoke detectors use ionizing radiation to detect particles in the air. The smoke is then drawn into the detector and converted into an electrical signal. Photoelectric smoke detectors use light to detect particles in the air. The smoke is then drawn into the detector and converted into an electrical signal.

Both types of smoke detectors work very well, and there is no significant difference in performance between them. The decision is based on which type of detector you prefer and which one will be more convenient for you to install.

Which is better hardwired or battery smoke detectors?

A hardwired smoke detector is a better choice than a battery smoke detector. Hardwired smoke detectors are more expensive, but they last longer and are easier to install. Battery smoke detectors are not as reliable and are also more expensive to replace.

Can a duct detector be used as an area smoke detector?

Yes, a duct detector can be used as an area smoke detector. Duct detectors have a very high sensitivity. You can use a duct detector to detect smoke in the air coming from a fire. If you have a duct detector installed in your home, it is possible that you will notice a change in the sound of the detector when a fire is occurring.


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