But when it comes to safeguarding your space, standard smoke alarms aren't your only line of defense — and using the wrong device in the wrong room could leave your home unexpectedly vulnerable. Enter heat detectors: a lesser-known alternative that operates on an entirely different set of rules. Heat detectors only kick on when a room gets dangerously hot or experiences a sudden temperature spike. Smoke detectors, however, trigger at the first presence of airborne smoke particles from smoldering fires long before high temperatures build up, providing early warnings to give occupants time to evacuate. Because sensor sensitivity degrades over time, knowing how often you should replace your smoke detectors is crucial — especially since smoke detectors react much faster than heat detectors, making them your primary line of defense for saving lives rather than just property.