It’s not common knowledge, but there are four main types of fire alarms. Which do you need to best protect yourself and your loved ones in the event of a fire?
Read on to find out all you need to know about keeping yourself safe, including the most commonly used type of fire alarm, the different types of fire alarm signals, and our recommendations for cheap and effective alarms.
Table of Contents
What Are The 4 Main Types of Fire Alarm Systems?
Smoke detectors are categorized as either ionization detectors or photoelectric detectors, while combination alarms use both types of smoke detector for maximum coverage.
Heat detectors are a fourth type of fire alarm system used in areas with an excess of smoke or steam, like the kitchen.
Learn more about each of the four types of fire alarm below.
1. Ionization Smoke Detector
A small piece of radioactive material ionizes (charges) the air between two plates. This creates a current that flows constantly. Particles that enter the device weaken the current, while smoke will reduce it below a threshold, sounding the alarm.
Pros
- Responsive to flaming fires (black smoke)
- Cheaper, and most common type in homes
Cons
- More unresponsive to smoldering fires (lighter, larger, reflective particles)
- Older technology
2. Photoelectric Smoke Detector
Instead of using radioactive material like an ionization detector, a light beam is shone inside a chamber. It won’t strike the detector if the chamber is free of particles. If smoke is present, the amount of light reflected will pass a threshold, causing the alarm to sound.
Pros
- Responsive to smoldering fires (light smoke)
- Newer technology
Cons
- More unresponsive to aggressive fires (black smoke)
- More expensive than ionization detectors
3. Combination Fire Alarm
As the name suggests, some fire alarms combine both photoelectric and ionization detectors to maximize use and protection against different kinds of fires.
Combination fire alarms are the best smoke detector, because they are the most responsive to all types of fire.
Pros
- Responsive to both smoldering fires and flaming fires
- Reliable
Cons
- Potential for false alarms may be higher since it is more sensitive
4. Heat Detectors
In areas where smoke is expected, like the kitchen, smoke detectors are of no use, since false alarms will be common. Instead, heat detectors should be used in kitchens and potentially near bathrooms.
A heat detector alarm sounds when it detects the temperature has exceeded a high threshold, indicating the presence of fire.
Pros
- Reliable way to monitor kitchens
- Significantly less chance for false alarms
Cons
- Will only sound when a fire has already become aggressive enough to cause a massive increase in temperature
What 2 types of detectors should you have in your house?
A home should be equipped with smoke detectors and heat detectors to get the best protection from residential fires. Place smoke detectors (either ionization, photoelectric, or a combination) in the main shared areas of the house, like hallways.
Place heat detectors in areas where smoke or steam are common, like kitchens or outside bathrooms. Although it won’t protect you from fires, a carbon monoxide alarm should also be placed in the home to protect you from CO poisoning, namely anywhere there’s a fuel burning appliance (the kitchen, for example).
Best Affordable Fire Alarms & CO Alarms
Below are our picks for the best types of fire alarm on the market, including ionization smoke detectors, photoelectric smoke detectors, and heat detectors.
We’ve also included carbon monoxide alarms, which are important for monitoring CO levels where fuel-burning appliances are located.
Find the best alarm that works for you.
Nest Protect (Battery)
Available on Amazon. From $116.49.
Pros
- Split spectrum sensor makes it accurate regardless of the state of the fire
- Combines smoke and carbon monoxide detection
- Push notifications let users know when and where something has occurred in real time
Cons
- Expensive
- The battery version requires six batteries in each unit
A bonafide smart alarm, it combines smoke and carbon monoxide detection as well as a ‘split spectrum sensor’, meaning it can detect smoldering fires just as well as it does flaming fires.
It’s also capable of detecting steam to avoid false alarms, and notifies phones so that even when the home is absent, occupants can be notified. No annoying chirping either—it’s a smart alarm, after all, so expect polite ‘conversation’ instead.
Kidde Smoke & Carbon Monoxide Detector
Available on Amazon.
Pros
- Combines smoke and carbon monoxide detection
- Affordable
- Voice alert
Cons
- Date of ‘manufacture’ is given rather than of expiration, which would be a much more clear way to indicate when it needs to be replaced
- Doesn’t have a photoelectric sensor, so won’t be as responsive with thick smoke
For those that don’t want to fork out on a smart alarm, this option from Kidde is the next best thing at a fraction of the price. A battery-powered smoke and CO detector, this failsafe option from well-regarded alarm experts Kidde is affordable and robust.
Chirping is absent, instead using a voice that states either ‘Fire! Fire!’, ‘Warning! Carbon Monoxide!’, or ‘Low Battery’. Suffice to say, there won’t be any confusion as to what it’s trying to communicate…
Ecoey Smoke Alarm
Available from Amazon. From $59.99 for 8 units.
Pros
- Come with up to 8 units in a pack, making it an affordable choice for larger spaces that need multiple units
- Photoelectric detector detects light smoke well
- Easy install, batteries included
Cons
- Chirping can be irritating
- Lacks an ionization sensor, which better detects thick smoke
This simple to use photoelectric smoke alarm comes with up to 8 alarms, allowing for maximum coverage of even the largest of properties. Batteries means users don’t need to worry about a power outage in the event of a fire.
It forgoes complicated features for an average user experience, although each unit is smaller than the average alarm, making them a little less unsightly. Despite the size, the alarm sounds loudly, clocking in at 85db.
BRK Heat Alarm
Available on Amazon. From $21.91.
Pros
- Hardwired for a long lifespan, with battery backup
- Ideal for areas that can’t be monitored by smoke detectors
- Remote testing possible
Cons
- Remote control sold separately
- Chirping can be annoying
- Hardwiring often requires an electrician
Since a fire is more likely to start in the kitchen than any other room in the house, a heat alarm is the only way to monitor it without experiencing constant false alarms.
BRK’s heat alarm will sound an 85db siren if it detects either a temperature of 135 degrees Fahrenheit or a temperature increase of more than 15 degrees Fahrenheit in under a minute—both of which strongly indicate the presence of a fire.
It markets itself as hardwired, but is capable of functioning solely on its battery backup.
Kidde Carbon Monoxide Detector
Available on Amazon. From $22.
Pros
- Affordable
- Plugs in to wall and has battery backup
- Batteries included
Cons
- Chirps and beeps
- No voice alerts
Having a carbon monoxide detector in your home is just as important as having a smoke or heat alarm. Having all three makes for a much safer home.
CO is a silent killer: it can’t be seen, smelt, or heard, so the only way to accurately detect dangerous levels of it is through a detector. This one plugs into the wall, but also features battery-backup for power failures.
What Are The Most Commonly Used Type of Fire Alarms?
Combination fire alarms, which combine an ionization smoke detector and a photoelectric smoke detector, are the most commonly used type of fire alarm.
Because they provide maximum coverage for all types of fire, most fire alarms manufactured nowadays combine both types of detection.
Combination fire alarms detect light smoldering fires and aggressive, smoking fires equally well. This makes them the most useful type of fire alarm for homes.
Is your fire alarm producing too many false alarms? Find out the cause and stay protected in your home. Minus the beeping.
FAQ
How many types of fire alarm are there?
There are four main types of fire alarm: ionization smoke detectors, photoelectric smoke detectors, combination alarms, and heat detectors. Of these four types of fire alarm, some are battery powered and some are hardwired.
Which smoke alarm is most common in residential areas?
Combination alarms are most common in residences. These combine photoelectric and ionization smoke detectors to maximize coverage for all types of fire, making them most reliable.
Is it better to hardwire a smoke detector?
Hardwired smoke detectors last longer than battery-powered ones, meaning less annoying chirps and beeps in the long run. They also usually have a backup battery inside them, meaning they are more reliable than ones powered solely by batteries.
However, hardwiring is a lengthy install process, and it can’t be moved as easily as one powered by batteries.
Conclusion
There is a need for both ionization and photoelectric smoke detectors, so neither type of fire alarm is fairly described as ‘better’ than the other. Instead, combination fire alarms are the best type of fire alarm for residences.
It is also recommended to place a heat detector in areas where smoke and steam are expected, like the kitchen, since smoke detectors won’t be useful in these areas. CO alarms are also important for preventing carbon monoxide poisoning.