Why would your lights flicker when your AC unit comes on and how can it be fixed?

Answer 1

Actually I have experienced this problem, as I bet have a lot of other people. An AC uses a large amount of electrical current. Whenever it switches on it causes a temporary power drain and lights will often dim or flicker. My neighbor is a retired electrician from Boeing Aircraft. He said it wasn't dangerous ,and the easiest and cheapest way to eliminate the problem was to limit the use of other electrical appliances. Like running the dishwasher late at night, when the tv(s) were off. Or the washer and dryer separately. Turn off all lights that weren't needed, etc. To prevent your lights from dimming you should have your AC unit on a separate circuit run directly from the main panel. The lights are flickering or dimming because the AC unit draws a lot of current when it starts up causing the voltage to drop on that circuit. Lights are sensitive to voltage fluctuations. Contact a HVAC professional and ask about installing a "hard start kit" on your AC compressor unit to prevent it from drawing the extra power from the house on startup. Some models already have built in supression circuitry and some don't. Yours probably doesn't.

Answer 2

Lights flickering when the AC unit comes on can be caused by a sudden draw of electrical power, causing a momentary voltage drop. This could be due to the AC unit and lights being on the same circuit or a loose connection in the electrical wiring. To fix the issue, have an electrician check the electrical wiring, ensure the AC unit is on a dedicated circuit, and consider installing a voltage regulator or power conditioner.