Thank you very much, ion, for that very clear explanation. If you don't mind, what is a single pole vs. a three-way dimmer? Also, do I de-rate the dimmer switch to 500 if two dimmers are in the same three-gang box, but at the ends?

Do I have to read each can light fixture to see what each is rated, or can I just assume that everything is 100 watts?

Thanks again!

Hmm. I just counted the kitchen can lights. We have eight cans on one light switch. Does that mean they can't be dimmed at all? (I haven't researched it extensively but so far the highest I've found is 600 watts.)

I you have two switches (like one at each end of a room) that both control the same light, these switches (in all likelihood) will be three-way switches. If you want to dim those lights, typically you would replace one of the three-way switches with a three-way dimmer.

If there is only one switch that controls the lights in question, you can replace that switch with a single pole dimmer.

If there are three or more switches controlling a single light, two of them will be three-way switches, and the rest of them will be four-way switches. And typically you would only be able to install a dimmer by replacing one of the three-way switches in that circuit, not by replacing one of the four-way switches.

Many light fixtures have maximum wattage ratings that are less than 100 watts. Count up the actual rating, not just assume 100 watts.

Thanks Bob,

I really appreciate your response. Now I need to figure out how to get to my 11' ceilings to read the fixtures. (I don't climb ladders!)

Thanks again!

Hi Meg;

Your posting comes at a providential time (for me): just yesterday I spent way too long researching this stuff online. Head-spinning! A useful site (for me) was Dimmers.net because they have so many choices for single-, three- and four-pole switches / dimmers. Their customer service (which I called twice) is okay -- they're clearly oriented toward people who already know what they're doing (which I didn't). But on each leading page (see here for an example) there's a useful list to check off your requirements, and then you'll be redirected to a page with what you need.

I was after plates / switches to color match and they have a great selection. I certainly appreciated that! Plus, in the same room I'll have a low-voltage as well as an incandescent fixture, so I was able to get switches which look the same but which function differently.

Good luck!

Thanks rmkitchen! So I'm not the only one with a spinning head.

Yesterday I waited five hours for the electrician. When he finally got here, he scared me away from a couple projects because he made them seem like they would be very messy and difficult. I started the dimmer research in a very bad mood. (The dimmers weren't going to be messy or difficult but when he mentioned that each switch would be about $60 and that I could probably get them cheaper online, I hit the computer.)

I still don't know if Decora is a brand or a type of switch! And I need to go to a real store to see whether we have almond or ivory. But it will get done!

Thanks so much for the link!

Check in the electrical department at HD or Lowes. They are no where near $60 each unless you want them in a custom color, in which case it would be better to order on line anyway. A specialty type dimmer will be more expensive but I think $60 is excessive for anything residential.

Decora is a style of switch

Also,

You only need to de-rate the dimmer if the fins on the dimmer are trimmed off. If you can fit two at opposite ends of a switch box without trimming they would retain their full rating.

One other thing to keep in mind - as another poster said, if you are using compact fluorescents (CFLs) you cannot dim them UNLESS you have dimmable CFLs which are now available.

Second, some dimmers will "hum" when dimmed, so it may be worth spending some additional $. I've had some cheap dimmers that both hummed and didn't allow for full brightness when turned all the way up.

More specifically, Decora is a form factor. Decora switches use switchplates with big rectangular openings for the buttons, like in the pic above. Other dimmers work with standard switchplates that have a much smaller hole in them, like standard toggle switches.

Thanks Dave. So to get an exact match, do I need to know what brand of switches I have?

Thanks to you, too, Jon and antiquesilver! (I started to write the response and got interrupted, and then posted before seeing your responses.)

You're all a wealth of info!

Meg -

The brand probably doesn't matter. As John said its a form factor thing. If you want them to look the same as other switches (of the same form factor) in the house it probably doesn't hurt.

In our house we have switches from $$ Leviton down to some cheapy HD ones in locations where they don't get flipped a lot.

I was looking at the Leviton because before I knew better, I thought Leviton Decora was the company name. LOL. Has anyone had any problem with humming from a Leviton SureSlide dimmer switch?

My hubby insisted on Leviton switches, and I don't want to know what the total cost is- he's put them everywhere! That's the price you pay for marrying an electrical engineer! We did find out though that you don't want to put both switches (if you have three-ways) on dimmers. Cuz, if you've dimmed down to half let's say on one, then you can't go any more than that on the other! So, be sure to save yourself some $$$ and extra work, and only put one dimmer per circuit.

He also picked the switches that glow in the dark when they are turned off (so you can find the switch at night). We are having problems with CFLs flickering when off with those ones. He thinks it's because the bulbs are at the end of their life cycle and are responding to the low voltage current needed to keep the light on in the switch.

raehelen -- actually, you can have more than one dimmer on a three-pole. In our former house (and what will be in this house) were Levitron's Maestro dimmers: the dimmers communicated via radio, so we could control the light / dimming with either control. The light was never "locked" in whatever position / brightness. Now, we did have to leave the little how-to-use sticker on the switches for a month or so because they are not intuitive, but then we got the hang of it.

And you can bet they are expensive! I just ordered four Maestro dimmers (low voltage) for our dining room and it came to ~$450. For one room. I am rationalizing it that they'll be color matched to the walls and I'll be grateful for that for years to come, but man!

I really like the paddle switches, though ....

My husband is also an EE but I'm the one pushing for the Decora switches -- I really like function married to form.

raehelen,

So now you have me thoroughly confused. I thought that, even with a Sure Slide, you can have two dimmer switches in the same three gang box. And what's the point of having two dimmer switches there if you can't dim them at the same time?

rmkitchen: that's a hefty price tag for dimmer switches. I like the sliding dimmers because there's no learning curve. When we were looking at houses and I came across some of those touch pad dimmers, I could never get them to work which was very frustrating.

I'll have to check them out. DH is not an EE so I don't think he'll care either way.

Meg,
Be sure to check out the Lutron dimmers. I've used them in restorations for the past 20 years & have found them to be quiet & very reliable.

If you have a light that switches on from 2 or more locations, normally you only put a dimmer on the location where the power source begins; you have regular 3 way switches on the other location(s). This has nothing to do with how many dimmers you can put in a box. You can put 2 dimmers (going to different fixtures) in the same box, regardless of whether they are single pole or 3 way. At least that's the way I remember it on incandescant lights - I know nothing about low voltage.

FYI - Electrical plate covers/switches/receptacles/dimmers, etc that have one large opening (as opposed to the ordinary small openings) are a style/shape referred to as "Decorator". Levitron & Lutron are brands & their particular model series are Decora, SkyLark, etc. Hope this brings some clarity.

Antiquesilver, thanks for clarifying the Decora/Decorator distinction. I missed that.

I went back and looked. Our dimmers are all Lutron and we've never had an issue with any of them.

The first two types below are available in 600w and 1000w capacity versions.

We have these which are great because you can leave the light level set and turn them off/on separately (ours have a night light not shown on this picture):

{{!gwi}}

We've also used these which are also available with a second mini slider to control ceiling fans:

And of course the most complex - for the master bedroom - remote dimming, on/off and preset levels

{{!gwi}}

Here is a link that might be useful: Lutron

At one time I was under the impression that by using an entry way light that has 9 bulbs on a dimmer, I could save on power costs by dimming it way down. But I've noticed that the dimmer I set it the warmer the area near the switch gets. I now assume that it may use diodes or something that lowers the voltage and changes the difference into heat. So maybe the consumption of current is the same regardless of the setting from max to min. Anyone know for sure?

No, the power consumption isn't the same. The dimmer consumes a little bit of power, but doesn't even come close to making up for the decreased power consumption at the fixture. FWIW, the bulbs do lose efficiency when dimmed; making them half as bright doesn't mean you're saving half the energy.

I'm gettng quite the education here. Thanks for all your help!

Hi Meg,

Yes, there is so much to learn. Really we live in such a wonderful world, that one can only touch the surface of all that is out there!

It's so funny that these Leviton switches mean so much to my DH. :>) I mean, basically I have had to make almost ALL the decisions about the total house reno, but this is his baby, and so I have let him go at it! Thank God he doesn't seem to be aware that the radio controlled switches exist, or I'm sure he would have installed those too!

So, to clarify, with the 'regular' dimmer switches (and as you now know, there are many choices), you can't have more than one per circuit, ie our kitchen pot lights- one switch is on a dimmer, the other (3-way) switch for those lights at the other end of the room is just an ordinary 'Decora' switch. But, you can have two dimmer switches in the same gang-box- they are for different circuits obviously. I have included two pics, one is with the lights on, one with the lights off.

OK- I have tried to resize the dark pic 4X, and it still appears big when I preview- sorry, but I give up!

"Decora" is a Leviton registered trademark. Other companies refer to this style as decorator or designer when they want to imply that their device fits the same size opening.

Lutron uses the name "Maestro" for one of their dimmer lines that fit in a designer style opening.

Maestro dimmers that you find at HD or Lowes are not RF radio frequency. Some have IR capability but are called Maestro IR, or identical looking Spacer. For 3ways you use a remote in wall that talks to the master dimmer and tells it what to do using the typical 3way wiring.

Lutron has both toggle style and designer style dimmers that can use remotes for mulitlocation dimming so you can have full control at both ends (and middle).

Lutron Radio RA and HomeWorks wireless systems do have RF Maestro dimmers for whole home capable lighting control systems that are easy to retrofit.

As Jon says, dimmers do save money, are an approved method of meeting California Title 24 in rooms as specified, do waste about 1% as heat at the dimmer and the lamps are not as efficient when dimmed. They also extened lamp life.

Some dimmers do not need to be trimmed to fit next to each other but still require derating for the heat they produce. There are 1000 watt models available as well as completely remote dimming where you put a normal dimmer in the wall to control a larger dimmer hidden away.