How can one verify that a smoke detector is functioning properly?

Verifying that a smoke detector is functioning properly is primarily accomplished by pressing the test button. This action activates the internal mechanism of the smoke detector, simulating the presence of smoke and triggering the alarm if the unit is operational. It offers an immediate check that the device is able to detect smoke and alert occupants, which is crucial for safety.

While changing the batteries, cleaning the detector, and replacing the unit can contribute to the overall functionality and maintenance of the smoke detector, they do not provide an immediate verification of the detector's operational status. Changing batteries ensures the device has power, cleaning helps maintain performance by removing dust and debris that can impede functionality, and replacing the unit addresses situations where it may be outdated or malfunctioning. However, none of these methods confirm in real-time whether the smoke detection mechanism itself is working as it should, which is why pressing the test button is the most direct and effective method of verification.