This heat detector offers fixed temperature or combination rate-of-rise and fixed temperature detection, suitable to any household or commercial applications. The detector is made up of an externally mounted thermistor with a specially designed cover that protects the thermistor while allowing maximum air flow. The thermistor reads the temperature from the air it takes in and transmits a signal representing the temperature to the panel. If the temperature reaches or exceeds the trip point or the temperature increase reaches or exceeds the rate-of-rise, the detector is triggered. The status LED lights in red and alarm signal is output. The detector is an ideal unit to detect rapid fire developments in houses, shops, hotels, restaurants, offices, schools, banks, libraries and etc.