Even if there is a market for specifically designed ammonia sensors, room temperature and long-term stable detection of low trace airborne ammonia represent a serious challenge that calls for immediate alternatives. This communication reports single-step hydrothermally engineered ZnCo₂O₄ nanoflakes for developing energy-efficient and economic ammonia-detecting chemiresistor. The formation of ZnCo₂O₄ nanoflakes was revealed through scanning electron microscopy. The X-ray diffraction outcomes reveal the crystal structure of ZnCo₂O₄ to be of cubic phase and Fd-3m space group. Optical absorbance analysis exhibits the optical band gap of the ZnCo₂O₄ nanoflakes to be 2.71 eV. Further, a chemiresistor was fabricated and used as the ambient room temperature ammonia sensor. The sensor exhibits a superior sensing response of around 34.13 for 30 ppm of ammonia, whereas at 5 ppm the sensor response of 3.49 with prompt response and recovery times of 1.52 s and 2.12 s respectively. The fabricated chemiresistor demonstrated excellent sensing performance in terms of 3 essential S’s (Selectivity, stability and sensitivity) and 5 R’s (Recovery, response, range, room temperature operation and repeatability). The enhanced sensing performance in an energy-efficient module is attributed to nanoflakes morphology of engineered ZnCo₂O₄ with a high surface area and its stable crystal structure.