Why Are My House Lights Dimming?

by | Sep 18, 2015 | Blog, Electrical | 0 comments

Solutions for dim lightingWe’ve all seen it from time to time, that tell-tale dimming of the lights in a room.  Usually there’s an action associated with it, such as running a microwave or a space heater, but then there are times when all of the house lights flicker or dim for no reason.  Sometimes this depends on the bulb you’re using, while at other times it has to do with your home’s wiring.

Aged Lighting

Bulbs and lamps dim over time; it’s an effect of age and is what the “life hours” tag on a bulb is actually talking about.  When a light bulb says it has a lifespan of 2,000 hours, it means that after 2,000 hours it won’t be putting out as much light as it used to (roughly 70% in fact).  As bulbs grow older, different components fail at different rates.  Incandescent filaments can become brittle and the light can flicker or dim intermittently.  Change out the bulb and the problem should be fixed.

Faulty Ballasts

Other issues you’ll find are electrical in nature.  While some, such as a faulty ballast, can be corrected by most people, we strongly advise hiring a licensed electrician for any electrical work.  Boulden Brothers does offer some electrical services so you can always call us.

Electrical ballasts regulate current or voltage flow to a light fixture.  The ballast supplies the lamp with the right amount of power at the right voltage frequency, and keeps it there (many ballasts also regulate special start-up conditions required by the lamp).  As a ballast ages, this regulation can become inaccurate.  The voltage or current level supplied can increase or decrease, leading to lights that are too bright, or lights that dim and buzz intermittently.  A licensed electrician can replace your ballast easily, or you can read the ballast’s label to purchase a replacement.

Circuit Overloads

If your lights flicker or dim whenever you turn on an appliance (e.g. a washing machine, vacuum cleaner, or microwave) then you’re beginning to overload your circuit.  Each home electrical circuit has a limit on just how much power it can draw.  As more devices are added to a single circuit (using power strips and outlets on the same circuit), the power demand increases.  At certain point, the current flowing through your lights will decrease to balance out this demand.  The lower current flow leads to dimmer lights in the room.  At this stage it isn’t really a problem, but if you plan to add heavier load devices we advise moving them to a separate circuit, or having a new circuit installed to account for the heavier load.  Otherwise, the increased demand will exceed the rated capacity of the line and you’ll need to make regular trips to the circuit break box to reset a tripped breaker.

Faulty Wiring

Sometimes, the issue is in your home's wiring.

Sometimes, the issue is in your home’s wiring.

Old, damaged, or poorly installed wiring is a common cause of dimming house lights, and can be one of the more dangerous causes.  Contact points for your house wiring and your fixture can become corroded over time, leading to poor conductivity and intermittent dimming.  The same thing can happen in your wall switches, where internal arcing leaves carbon buildup on the electrical contacts.  Frayed or damaged wiring can sometimes lead to dimming and is extremely dangerous.  If you suspect faulty wiring you should always contact a licensed electrician as soon as possible.  One last place to have an electrician inspect if you can’t find the cause of the dimming is the breaker box itself.  If the neutral wire has loosened or become corroded over time, then dimming is possible and it should be replaced before it becomes a bigger issues.

Faulty wiring in the form or corrosion, frays, loose connections, or improper installation is all serious safety hazards and should be addressed by an electrician.  Do not try to correct home wiring issues yourself.

Power Grid Issues

One final possibility is a power grid issue.  If there are any abnormalities on the overall power grid it could affect the lighting in your home.  Increased demand (similar to the home circuit overload) on your city block or neighborhood can lead to enough of a power difference that your lights dim.  When there is an excessive city-wide power demand, a brown-out condition occurs which leads to dimmer house lights.

Obviously this is not an exhaustive list of lighting dimming issues.  Most issues with dim lighting are electrical in nature (having little to do with the bulb itself) and will require an electrician.  But it can save you both time and money to know what the issue is in advance before scheduling an appointment.


Dimming or flickering lighting is annoying, it doesn’t matter when it happens.  For electrical services, Boulden Brothers is the right choice if you are located in the greater Wilmington & Dover, DE area.

If you have any further questions home wiring, talk to the licensed, trained technicians at Boulden Brothers.

Visit us on our websiteFacebook, Twitter, and Google+ or give us a call at (302) 368-3848 for more information on maintaining a Green home. We are available 24 hours a day, 7 days a week to answer any questions you might have.

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