What Are the Causes of Lights Dimming?

Weather

• Inclement weather conditions present one of the causes for intermittently dimming lights; heavy winds and thunderstorms can make this happen. Objects touching the power lines make lights dim or flicker. For example, wind causes tree branches to hit power lines, but they don't always break the wire. Dimming could also be a sign that the power will go out soon. The lights may stop dimming after the worst of the weather has passed.

Brownout

• Excessive regional electricity demand sometimes causes dimming lights or electrical outages. A technical failure at a power plant in the area may also create this problem, because available electricity becomes insufficient to meet the demand. Very hot weather can produce brownouts, because people use more fans and air conditioners. Cold weather also causes brownouts, especially in regions where many people use electric heat. Local radio or television news programs may provide more information.

Bulbs

• If the dimming occurs in only one lighting fixture, it may indicate the failure of a single light bulb. Fluorescent bulbs sometimes develop problems with dimming as they age. Replace the bulb with a unit of equivalent wattage, and recycle or dispose of the old bulb properly. If the dimming continues, the building may have a wiring problem.

Wiring

• One of the more problematic causes of dimming lights is the failure of household wiring. If dimming persists despite calm weather conditions, and the local power company doesn't report any problems, contact your landlord or an electrician. Dimming of this type may occur when appliances turn on. Potential causes of wiring issues include rodents, problem drywall and flooding, among others.

Other Causes

• Several other potential causes of lights dimming remain possible, but less likely. Fuel in your generator or energy in the battery of your recreational vehicle may be running out, if your lights obtain power from one of these sources. Issues with a remote-controlled dimmer or a home automation system connected to the lights could also create such problems.