Fire – it’s every householder’s worst nightmare.  Two of the most commonly used tools you can use to protect your home and life against fire are smoke detectors, and heat detectors.   Let’s take a look at both of these products.  How do they compare?  Do you need both?  Which one is going to work better for you?

Let’s deal with the last question first – ‘which one is going to work better for you?’  Well, in terms of appliances, this isn’t a question of better, because smoke and heat detectors do different things and both of them fulfil necessary functions.  Let’s look a bit closer at the two technologies. 

Smoke Detectors

Source: Which

A smoke detector is a fire – protection device that automatically detects and gives a warning of the presence of smoke.  The 2 most common types are ionization smoke detectors and photoelectric smoke detectors.

Heat Detectors

Source: CPSC

A heat detector is a fire alarm device that responds when the convected thermal energy of a fire raises the temperature of a heat sensitive element.  These devices essentially sense heat produced by combustion.

Now, looking at the two images above, you can see the problem – both devices look virtually identical, and this is what leads to confusion and puts YOUR safety at risk

Let’s compare the two in a table:

CaseSmoke DetectorHeat Detector
Made to ProtectLifeProperty
Works viaionization or photoelectric effectthermocouple or electro – pneumatics
Powered byBatteries or household electricityBatteries or household electricity
PlacementAll areas of the home or property excluding kitchen/food preparation areas or designated smoking areasKitchen, garages, cellars, designated smoking areas or any place where flammable/combustible materials are stored
False Alarms?PossibleNo
Required by Law?Yes, in most states*Not usually, but check your state guidelines*
Smoke vs Heat Detectors – Compared

* You can easily check the legal requirements for your state by visiting:

It is important to note that in many cases the occupants of a house can be affected or even die from smoke inhalation BEFORE the heat detector is triggered, as some fires can be slow smoldering.  That is why it’s best to cover your bases and install BOTH types of devices.

Heat detectors are designed primarily to protect property from fire, for example goods sitting in warehouses, thus their application is mainly industrial.  By contrast, smoke detectors are designed to give early warning to humans in a residential setting, thus their application is mainly domestic.

What You Need To Know

  • As with any appliance, smoke and heat detectors need to be understood and installed and maintained correctly – so read the manufacturer’s manual thoroughly and keep it for reference.
  • Whether you’re using battery powered smoke detectors, heat detectors, or both – your devices are only as good as their batteries.  The U.S Fire Administration (U.S.F.A) recommends testing your devices once a month and replacing the batteries once or twice a year.
  • To be totally secure in the performance of your detectors – replace the batteries entirely even if they still have ‘life’ left in them.  Use these still viable batteries in other appliances or keep them as spares for usage elsewhere.  Don’t be tempted to skimp on batteries for smoke and heat detecting devices:  it may cost you your life.
  • For whatever fire signaling/prevention device you are using, the entire unit should be replaced every 10 years, and fitted with new batteries
  • Smoke alarms should be installed at least 3 meters/10 feet from cooking appliances to minimize false alarms.
  • Heat detectors should be ceiling mounted near the center of the room, at least 300mm away from light fittings and at least 300mm away from walls and corners.
  • Smoke detectors should be placed high on walls or on ceilings because smoke risesWall mounted detectors should be not more than 12 inches away from the ceiling
  • If you have sloped ceilings, install the smoke detector within 3 feet of the peak, but not within the apex of the peak.
  • Never paint or decorate your detectors in any way – stickers, paint or adhesives may interfere with the unit’s operation and render it unsafe.
  • Buy all of your detectors from the same manufacturer.  If their alarms are interconnected, they will interface and work together safely.  This may not be the case for units of different models/makes – they may not ‘talk’ to each other, thus no alarm will be sounded in the event of fire.
  • Garages are a common source of fire, so don’t neglect this area of your home, install detectors there too!
  • Keep smoke and Carbon Monoxide detectors separate, and don’t rely on units that promise both types of detection.  Smoke rises towards the ceilings, whereas Carbon Monoxide settles at around knee level, so the two detectors need to be placed at those heights.
  • If your fire and smoke detecting units are going to be running off electricity (hardwired) instead of batteries, CHECK that the model you are buying comes with an internal battery back – up system that will keep them working if your electricity supply is interrupted.
  • Safe Disposal:  Photo electric smoke detectors are safe to put into the trash, as long as you remove the battery first.  Ionization detectors contain a small amount of radioactive material so you should never dismantle them yourself.  For ionization based detectors, contact a hazardous waste disposal center or send the entire unit back to the manufacturer, they will dispose of it safely for you.

Home Fire Safety: Best Practices

The smoke and heat detectors are doing their jobs and their alarms are sounding.  It’s time to exit the building safely.  Here are some pointers worth committing to memory.  Remember, in an emergency situation it’s important that this information is at the forefront of your mind, so refer back to this article and other resources regularly. 

We also recommend implementing a ‘fire plan’ and a ‘family emergency communication plan’ for yourself, your family and other building occupants.  In other words – make like a Boy Scout and BE PREPARED.

  • GET OUT, STAY OUT, and immediately call 911 or your local emergency service number
  • Yell ‘FIRE!!!’ as loud as you can several times then IMMEDIATELY exit the building.  If you live in a building with elevators, take the stairsLEAVE ALL PROPERTY behind, and save yourself. 
  • If closed doors or door handles are warm/hot to the touch, or smoke blocks your first escape route, use a second way out if there’s one available.  Never open doors that are warm to the touch unless there is absolutely no alternative.
  • If you have to escape through smoke, get as low as you can to the ground, and close all doors behind you.
  • If your escape routes are blocked by smoke, heat or flames, stay in the room you’re in with the doors closed.  Place a wet towel under the door and call emergency services.  Open a window or vent if you can and use something brightly colored or a flashlight to wave outside and signal for help.
  • If the fire is simply too intense and you are not on the ground floor, you may have to jump to safety as a last resort.  In this instance, throw out any blankets, pillows and soft items and try to position these where you expect to land.  Next, hang out of the window and try to lower yourself as close to the ground as you can before you let go and fall to the ground.  A fire – escape rope or steel ladder is such a vital safety tool to have for people who live in apartment blocks or other raised accommodation and they can be found at major retailers such as Walmart and Lowe’s.     
  • Once you are safely outside, go to your building/family’s designated emergency meeting area and send one person to call emergency services if this hasn’t been done already.  If you cannot get to the emergency meeting area, follow your family emergency communication plan.

If your clothes catch on fire:

STOP – what you’re doing

DROP – to the ground and cover your face if you can

ROLL – over and over and back and forth until the flames are extinguished. 

DO NOT RUN – this will make the fire burn faster.  

Once the flames are completely out, apply cold water to the burnt skin for 3 – 5 minutes and have somebody call for medical attention.


Below are a couple of links that you can access to get advice on fire safety, applicable legislation, as well as industry advice from the ‘hottest’ experts in the field – fire experts and fire fighters. – U.S Fire Administration – National Fire Safety Council – National Fire Prevention Association – Institute of Fire Engineers (global) – International Institute of Risk & Safety Management – Fire Fighter Safety Research Institute – The American Red Cross Organization

This article has aimed to be informative, and it is our sincere hope that you and your family will never have to face the destructive power of fire. 

Fire is an unfortunate daily reality though, with a house fire occurring roughly every 90 seconds in the U.S.  It’s as well to be prepared, so that both lives and property can be saved. 


I hope this quick guide has helped you understand the difference between smoke and heat detectors.

If it has, please consider supporting us by checking out the related articles below.

Thank you for reading. Stay safe, and have a great day!