Ordinary smoke alarms can only do this one thing
Defending against fire is a chief concern for homeowners, and smoke detectors take on a critical role in shielding your family. However, smoke detectors have their shortcomings. To illustrate, they can only react to smoke, not heat. If there is an emergency in your home, you would not be cautioned unless the smoke rises to the smoke detector. While there are additional unmistakable indications of fire -- such as a sharp increase in warmth -- if there's no smoke, there is no triggered smoke detector.
Additionally, smoke detectors only sound the alarm if they encounter ample smoke. If a fire starts small, you might not be alerted until the situation is out of hand. Many smoke detectors use more than one sensor, meaning they will detect smoke from both a raging fire and something less intense. If they start beeping, it falls to the occupant to notify first responders after safely leaving the property.