Q: What’s the difference between a “heat detector” and a “smoke detector”?
A: A heat detector (below) is used when a smoke detector is not optimal for various situations. It will trip when the heat reaches a specified temperature (135 or 194 degrees depending on model). By the time this occurs, you have a full-fledged fire. Due to this, it is not a life safety device. It is better than nothing, but not preventative.
A photoelectric smoke detector (below) has the ability to detect smoke before fire is present. This is provides you time to evacuated the area or respond accordingly. Smoke detectors are considered life safety.