FAQ: Why do my lights dim when my air conditioner turns on?

Having your lights dim when your air conditioner (or furnace) turn on can be bothersome but not necessarily an issue for concern. Air conditioners require a lot of energy to start up and so they draw extra power temporarily draining the electricity from other appliances such as your lights. For the most part, this is a normal occurrence if your bulbs dim for a brief second or less and your lights only dim about 5% of their brightness. If your lights dim longer or lose more of their brightness, there could be other issues such as damaged or loose wiring, a weak capacitor in the air conditioning unit, or the appliance is sharing a circuit instead of on its own. If you aren’t sure if the dimming is an issue, call your local certified electrician who can help you determine the cause.