Regular smoke alarms can only do this one thing
Protecting your home from fire is a chief concern for homeowners, and smoke detectors play an essential role in keeping your family safe. However, smoke detectors have various shortcomings. For example, they will only identify smoke, not high temps. When there is an emergency in your house, you might not be cautioned until the smoke ascends to the smoke detector. Even though there are further unmistakable indications of fire -- like a sharp increase in warmth -- if there's no smoke, there is no warning from your smoke detector.
Additionally, smoke detectors only beep if they encounter enough smoke. If a fire starts small, you may not be cautioned until the flames are out of control. Many smoke detectors employ more than one sensor, which means they will be able to perceive smoke from both roaring flames and a more gradual burn. Then when they sound their alarm, it falls to the homeowner to call the fire department after exiting the residence.