Wall switches make a buzzing sound after installing energy-efficient bulbs in the overhead fixtures?

You are hearing the frequency of the 60-cycle power line. Even the old incandescent bulbs could be heard if the room was quiet. The normal 60-cycle line is a smooth sine wave and is difficult for the ear to hear. A dimmer on the line is turning the power on at different points of the sine wave. This produces a high frequency that makes it easier to hear.

Electrical parts moving when current is applied cause the sound, although this movement is very small you are able to hear it. The movement is something like the action of a speaker. Even two wires side by side will pull at each other when current is applied. Semiconductors, like the Triac that is used in you dimmer, will deform with applied current. This also can make enough sound to be heard.

This is nothing to worry about but can get annoying once you start to think about it. You may be able to find some brands that have taken this into consideration and have minimize the sound.

Never use a dimmer switch with an energy saving lightbulb. It defeats the purpose. The dimmer switch wastes electricity. If you really need a dimmer switch, you need to buy a good quality one MK dimmer switches are about 80 quid but if i were you i'd switch back to a simple switch about 2 quid. Also each dimmer switch has a wattage rating and to avoid buzzing even on the cheap dimmers your not supposed to exceed 1/3 of this load. This is for standard light bulbs and will apply for energy efficient ones too, once they are fully on (not sure about start up but 10 seconds of buzzing wont drive you nuts).

Energy Efficient Light Switches

Just an opinion but I would never use a dimmer with a fluorescent (thats what those energy savers are) some of them are high frequency etc. I think you are getting a bad harmonic between the supply frequency in the dimmer and the bulbs. Have an electrician remove or bridge out the dimmer part.

(Energy savers have enough quality of light issues without trying to dim them. I have never seen it done well)

Standard dimmers are not designed to operate flourescents. This combination can cause early failure in either the dimmer or the lamp. This will defeat the benefit of having a lower electricity bill when you have to pay to replace prematurely failed lighting components.

WK

Inexpensive inductive dimmers will do this.

try a magnetic dimmer. they cost a little more

This site may help

http://www.lutron.com/service/FAQ.asp

Can you explain this please?

"And He cannot make a rock too big for Him to lift because He is eternal, which means He is God without beginning and without end"

I just cannot see ANY logic in this at all.

bulb is drawing too much current