National Home Inspector Practice Exam 2026 - Free Home Inspector Practice Questions and Study Guide

The correct choice is the CO detector, which is specifically designed to measure the presence of carbon monoxide in the environment. Carbon monoxide is a colorless, odorless gas that can be harmful or even fatal if inhaled in significant quantities. CO detectors function effectively by using sensors that can detect the concentration of carbon monoxide in the air and will typically alert occupants through alarms or notifications when dangerous levels are reached.

The terminology used in the other options might lead to confusion. Options such as OC detector and OC2 detector do not correspond to any recognized type of detector for carbon monoxide. The CO2 detector is meant to measure carbon dioxide, which, while important for monitoring air quality and ensuring adequate ventilation, does not provide safety against carbon monoxide poisoning. Understanding these distinctions is crucial for home inspectors and safety professionals in ensuring appropriate detection systems are in place for hazardous gases.