Ordinary smoke alarms can only do one thing
Protecting your home from fire is important, and smoke detectors take on an essential role in keeping your family safe. Despite that fact, smoke detectors have some shortcomings. For example, they can only react to smoke, not heat. When there is a blaze starting in your house, you would not be alerted until the smoke rises to the smoke detector. Although there are some other telltale indications of fire -- such as a sudden increase in warmth -- if you don’t have smoke, you will fail to get a sounding of your smoke detector.
What’s more, smoke detectors only beep if they find enough smoke. In the event a fire creeps along slowly at first, you might not be cautioned until it's too late. Various smoke detectors utilize dual sensors, meaning they will recognize smoke from both a blazing inferno and smoldering remnants. Whenever they sound their alarm, it falls to the homeowner to notify emergency services after exiting the premises.