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What is the difference between a smoke alarm and a heat alarm?

Friday, March 4, 2022

It’s simple enough: a smoke alarm detects smoke and a heat alarm detects heat. But there’s more to it than that. Smoke alarms are required in a residential setting where people sleep. Today’s code mandates one in each sleeping room, and also in the access area just outside the sleeping rooms. They recognize the presence of a fire quickly at the first sign of smoke, and awaken residents to give them time to escape the building before the fire spreads. 

    But the high sensitivity of smoke alarms has its drawbacks. False alarms caused by things like burnt toast or bathroom shower steam can be a problem, and they do not function well outside of conditioned living spaces. Extreme heat or cold, humidity, and dust can make them malfunction or fail. So smoke alarms are not recommended for installation in a garage, unfinished attic, or crawl space.

    Heat alarms, on the other hand, perform well in the same areas that are problematic for smoke alarms. They are also definitely the right type of alarm for a garage, where plenty of house fires begin due to the gasoline and flammable chemicals that are often stored there.

    The average heat alarm is triggered when the temperature exceeds 135º F or rises by 15º F or more in less than a minute. Unfortunately, an attic in Florida can easily reach above 135º F on a hot summer afternoon, so there are also heat alarms that hold off until 195º F before sounding the alarm.

    Electronic heat alarms can be interconnected with the home’s smoke alarms so that they all go off if a heat alarm senses a fire, and some even offer wireless connections. But, long before today’s high-tech microprocessor sensors, there were wind-up mechanical heat/fire alarms that were activated by an internal fusible link. To read about them, go to What is that strange retro-looking smoke alarm?

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Here’s links to some of our other blog posts about “SMOKE AND CO ALARMS":

What is the best place to install carbon monoxide alarms (CO detectors) in a house? 

Can the smoke sensors in a home security/fire alarm system replace the smoke alarms required by the building code?

Does pushing the test button on a smoke alarm test the smoke sensor device inside? 

Should a smoke alarm be installed in the kitchen? 

Where are smoke alarms required to be located? 

Are carbon monoxide alarms required to be installed in homes in Florida?

When should I replace my smoke alarms? 

Does the Nest Protect system meet current building code standards for a combination smoke and carbon monoxide alarm system? 

What does the new Florida smoke alarm law require? 

 Is there a Florida law that all older homes must have smoke alarms, regardless of when they were built? 

• Why are carbon monoxide (CO) alarms required by law for homes in Florida? 

• When were smoke alarms first required to be interconnected?

How can I tell the difference between a smoke detector and carbon monoxide (CO) detector? 

When were smoke detectors/alarms first required in Florida?

What is the minimum height for placement of a CO alarm (carbon monoxide detector)? 

Where does the code require CO alarms (carbon monoxide detectors)?  

• Is it illegal to disconnect a smoke alarm? 

• Where should smoke alarms NOT be installed?

• Does a home inspector test smoke alarms?

 Does a home inspector test CO carbon monoxide alarms?

• Why does my CO alarm (carbon monoxide) keep chirping after replacing the battery?  

What is the average life expectancy of a CO carbon monoxide detector?

• What is the average life expectancy of a combination smoke and CO carbon monoxide detector? 

Where should a smoke detector be placed on a tray (coffered) ceiling? 

• How close can a smoke detector be to a ceiling fan? 

• How close can a smoke detector be to an air conditioning/heating supply register (vent)? 

• How close can a smoke detector be to a bathroom door? 

• Are carbon monoxide (CO) alarms required in mobile/manufactured homes?

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