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Ionization vs Photoelectric Smoke Detectors

Did you know the vast majority of residential fire fatalities are due to smoke inhalation?

Contrary to popular belief, most residential fire fatalities are not from the actual flames and nearly 2/3 of fire fatalities occur at night while we sleep.

Did you know that there are two different types of smoke detectors?

Well, there are! Most installed alarms, (90%) are ionization models best suited for detecting cooking fires and other fast-flame fires — fires that typically start while people are awake and can escape. These alarms are also more susceptible to nuisance alarms from things such as cooking, burnt toast, and steam from your shower. Therefore, they are frequently disabled and residents are left unprotected.


While photoelectric alarms are more sensitive to smoldering fires in living rooms, bedrooms and kitchens, where heavy furniture, mattresses and synthetic countertops are more likely to burn slowly. These fires often start overnight, during sleeping hours.

So what does this mean to you?

Well, an ionization smoke detector can take 15 to 50 minutes longer than a photoelectric to go off during a smoldering fire! These are invaluable minutes needed to escape before you’re overcome by smoke. 

So how do I tell which type is in my home?

Take the detector down and look at the back, if there is a mention of radioactive material or the letter I in the model number, then it’s an ionization type. But, if you can’t tell, better safe than sorry and replace it with a photoelectric model.


When going to buy a smoke detector read don’t just pick the cheapest one, as they are often the ionization type so read the package carefully. Since they all look pretty much the same and it can be overwhelming when you are in the store, you can always ask an employee. Your life might depend on it.

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