The answer to 'why is my smoke detector dimming lights' is that a malfunctioning smoke detector can cause flickering or dimming of nearby lights. This is often due to an electrical issue with the smoke detector interfering with the home's electrical system. Smoke detectors are connected to the home's electrical wiring and can sometimes draw too much current, resulting in a voltage drop that affects the lighting.
Common causes include a faulty smoke detector, improper installation, or an overloaded electrical circuit. If the smoke detector is old or damaged, it may be drawing more power than it should. Additionally, if the smoke detector is wired to the same circuit as the lights, the power draw can cause the lights to dim or flicker when the smoke detector is active.