Dimmer noise

Virtually all dimmers are build around SCRs and Triacs and what they do, in effect, is turn the switch on and off really, really fast. Since conventional incandescent lights have a filament that doesn't respond that fast, the filament sort of averages the actual power its getting.

But, some other lights, like flourescents and halogens, don't like being switched on and off like that. I had a set of LV halogens on a dimmer in my dining room that made a huge racket when the dimmer was used. I replaced that dimmer with one meant to control halogens, and its been fine.

But, be aware that switching things on and off like that really fast really messes with the AC in your house. Most audiofools won't have a dimmer in the same circuit (even the same house) as a decent stereo. While newer dimmers may control noise coming from the switch somewhat, just be aware they are still (unless things have undergone some radical redesign I wasn't aware of) going to create ugly noise on your AC lines. You will hear that on your stereo.

Besides, dimmers don't work well with compact flourescents. You have changed to cheaper, more eco-friendly CFLs, right?

@Eldartford--I'd be interested to know which kind of dimmers you use. The ones I've seen have all relied on fast switching. There are those that tend to switch off on the downside of the AC waveform that are supposed to be friendlier to certain types of technology, but even those strike me as being pretty noisy.

With respect to the halogens, I think its an issue with the transformers for low voltage halogens--something in my lights audibly buzzed. Companies like Leviton actually make special dimmers for inductive loads designed to combat that--they run over $50 a piece. They do reduce transformer noise, but I still wouldn't put them in the same circuit as my stereo.

As far as the eco-friendly part, it was intended to be tongue in cheek. That said, I don't buy your argument. A CFL uses about 1/6th the energy of a standard incandescent. That represents energy savings for lighting--a bulb's principle purpose. Saying "yeah, but the energy of an incandescent turns into heat and I need heat" is a red herring--light bulbs are a hideously inefficient way to heat your house. The touted "heat replacement effect" has pretty much been discredited, as far as I know--in large part b/c incandescent bulbs don't distribute heat as well as a system designed as a heating system (this ignores higher efficiency heating systems as well). As I understand it, CFLs come out better in terms of overall energy consumption, cost, and CO2 emissions even considering heat replacement.

Point taken, but its the distribution of the heat in a useful manner, not the production of the heat, that I believe accounts for the difference.

I'll have to look at dimmers again and shop around. Getting the LV halogen dimmer was a special order at the time--couple years ago--and the price shocked me. It would be great if they were more broadly available.

I wouldn't doubt it. But, I still feel like for the overwhelming majority of the US population, going CFL is appropriately "green." (As a side note, I gather Home Despot is giving CFLs away this w/e for earth day.)

I would further note that ultimately anything I say here is probably hypocritical. While I haven't claimed to heat my house using light bulbs, I have tried to justify my vacuum tubes on that basis. ;)