# Hey electricians! Flourescent bulbs with a dimmer? **URL:** \ **Category:** Factual Questions\ **Created:** [August 31, 2006, 12:00am UTC](https://boards.straightdope.com/t/hey-electricians-flourescent-bulbs-with-a-dimmer/370853 "2006-08-31T00:00:20Z")\ **Posts on this page:** 12\ **Page:** 1
**Author:** ![Neptunian\_Slug](https://avatars.discourse-cdn.com/v4/letter/n/ce7236/32.png) [@Neptunian\_Slug](https://boards.straightdope.com/u/Neptunian_Slug)\ **Post date:** [August 31, 2006, 12:00am UTC](https://boards.straightdope.com/t/hey-electricians-flourescent-bulbs-with-a-dimmer/370853/1 "2006-08-31T00:00:20Z")
I just moved into my new place. The former owner had the house wired up with all kinds of 75 and 100 watt floodlights and dimmer switches. Quite attractive actually. I can only imagine that the electric bill in this place was enormous. Anyway in the old house, I used nothing but flourescent bulbs to cut my electricity costs and I want to install them here. Question, is there any problem with using the dimmer switches with flourescent bulbs? If I turn the juice down is there any chance that it have an adverse impact on the bulbs, like blowing them up or starting a fire? ---
**Author:** ![Harmonious\_Discord](https://avatars.discourse-cdn.com/v4/letter/h/74df32/32.png) [@Harmonious\_Discord](https://boards.straightdope.com/u/Harmonious_Discord)\ **Post date:** [August 31, 2006, 12:08am UTC](https://boards.straightdope.com/t/hey-electricians-flourescent-bulbs-with-a-dimmer/370853/2 "2006-08-31T00:08:34Z")
You can’t use dimmers with flourescent lights. You’ll have to have the switches changed. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [August 31, 2006, 12:08am UTC](https://boards.straightdope.com/t/hey-electricians-flourescent-bulbs-with-a-dimmer/370853/3 "2006-08-31T00:08:47Z")
IANAElectrician, but generally speaking, dimmers just plain don’t work with fluorescent lamps. You know how, when you turn them on, they sort of do a tick-tick-flash-flash thing, rather than starting off dim and fading up to full brightness\* - that’s because they’re really only ever on or off; there’s no in-between dimmed state they can be in - either there’s enough energy for them to function, or there isn’t, and if there isn’t, they don’t light up at all. \*(OK, I know they get brighter as the phosphor warms up) ---
**Author:** ![gazpacho](https://avatars.discourse-cdn.com/v4/letter/g/6f9a4e/32.png) [@gazpacho](https://boards.straightdope.com/u/gazpacho)\ **Post date:** [August 31, 2006, 12:31am UTC](https://boards.straightdope.com/t/hey-electricians-flourescent-bulbs-with-a-dimmer/370853/4 "2006-08-31T00:31:07Z")
You can get compact fluorescent bulbs that work with normal incandescent dimmers. You should be able to find them at Super Home Mega stores near you. ---
**Author:** ![Nanoda](https://avatars.discourse-cdn.com/v4/letter/n/ce73a5/32.png) [@Nanoda](https://boards.straightdope.com/u/Nanoda)\ **Post date:** [August 31, 2006, 12:45am UTC](https://boards.straightdope.com/t/hey-electricians-flourescent-bulbs-with-a-dimmer/370853/5 "2006-08-31T00:45:52Z")
I’m not sure what would happen with regular bulbs and a dimmer, but I’ve recently been obsessed with getting fluorecent bulbs all over my house (not until I find some that start up instantly though), and have seen at least three types of bulbs at [Rona](http://www.rona.ca/) that say on the box that they work with dimmers. IIRC, one was a flood-type light too. Assuming you’re in the 'States, I’d bet any large home renovation store would carry them. Before you buy a bunch, make sure they fit your light sockets though. The ballast on _some_ bulbs is fantastically small, but others won’t _quite_ fit in the smaller recessed sockets (like in my overhead fan, for instance) :smack: ---
**Author:** ![iamthewalrus\_3](https://avatars.discourse-cdn.com/v4/letter/i/258eb7/32.png) [@iamthewalrus\_3](https://boards.straightdope.com/u/iamthewalrus_3)\ **Post date:** [August 31, 2006, 12:47am UTC](https://boards.straightdope.com/t/hey-electricians-flourescent-bulbs-with-a-dimmer/370853/6 "2006-08-31T00:47:28Z")
I’m not an electrician, but the house I rent has a very similar setup. I tried to find information on this in the past, and it seemed like there _were_ some special flourescent bulbs that were built to work with dimmers (I assume that they have multiple elements and some sort of voltage stepper/transformer built into them), but it was hard to tell if they’d really work. I hope there is a good solution to this. ---
**Author:** ![kanicbird](https://avatars.discourse-cdn.com/v4/letter/k/5f8ce5/32.png) [@kanicbird](https://boards.straightdope.com/u/kanicbird)\ **Post date:** [August 31, 2006, 2:50am UTC](https://boards.straightdope.com/t/hey-electricians-flourescent-bulbs-with-a-dimmer/370853/7 "2006-08-31T02:50:41Z")
I have tried compact florecents on a dimmer, they just flickered. As mentioned there are some that can be dimmed. ---
**Author:** ![Neptunian\_Slug](https://avatars.discourse-cdn.com/v4/letter/n/ce7236/32.png) [@Neptunian\_Slug](https://boards.straightdope.com/u/Neptunian_Slug)\ **Post date:** [August 31, 2006, 4:19am UTC](https://boards.straightdope.com/t/hey-electricians-flourescent-bulbs-with-a-dimmer/370853/8 "2006-08-31T04:19:36Z")
I guess I was less interested in whether or not the lights will actually dim and more interested in whether I will burn my house down due to some inherent incompatibility of flourescents and dimmer switches. Some dimmers have an an on/off switch in addition to the dimmer. Mine do not so turning the lights off is more or less dimming them until they don’t shine any more. If there is a potential hazard then I will go replace them. However, if there is no problem, then the only danger is with me trying to do anything electrical in my house. ---
**Author:** ![danceswithcats](https://avatars.discourse-cdn.com/v4/letter/d/9e8a1a/32.png) [@danceswithcats](https://boards.straightdope.com/u/danceswithcats)\ **Post date:** [August 31, 2006, 4:23am UTC](https://boards.straightdope.com/t/hey-electricians-flourescent-bulbs-with-a-dimmer/370853/9 "2006-08-31T04:23:28Z")
TCP edison base fluorescent lamps will work with some dimmers, but may encounter difficulties when turned down too far. There are also some CFLs which look like a standard A19 incandescent lamp, but are fluorescent and dimmable. Rather than a big box-see your local lighting supply outlet or go smurfing on teh intarwebs. ---
**Author:** ![Placid\_Liver](https://avatars.discourse-cdn.com/v4/letter/p/e99b99/32.png) [@Placid\_Liver](https://boards.straightdope.com/u/Placid_Liver)\ **Post date:** [September 2, 2006, 6:01am UTC](https://boards.straightdope.com/t/hey-electricians-flourescent-bulbs-with-a-dimmer/370853/10 "2006-09-02T06:01:32Z")
So why can fluorescent tubes glow in an induced EM field but not run with a dimmer? couldn’t they be rigged to have full power to start, and then run at reduced power? ---
**Author:** ![Harmonious\_Discord](https://avatars.discourse-cdn.com/v4/letter/h/74df32/32.png) [@Harmonious\_Discord](https://boards.straightdope.com/u/Harmonious_Discord)\ **Post date:** [September 2, 2006, 12:26pm UTC](https://boards.straightdope.com/t/hey-electricians-flourescent-bulbs-with-a-dimmer/370853/11 "2006-09-02T12:26:28Z")
> [@Placid Liver](#): > > So why can fluorescent tubes glow in an induced EM field but not run with a dimmer? couldn’t they be rigged to have full power to start, and then run at reduced power? The circuitry has to adjust the power output on a flouresent bulb. Most flouresents adjust the ouput in the unit it’s self and require the the power isn’t on a dimmer. Aparrently some are now being made with circuitry compensate and allow for an external dimmer. There are different types of dimmers nnow and I wonder if the bulbs require a certain type. Some of the new one’s don’t drop the voltage with a resistance, but pulse the power on and off for different amounts of time. ---
**Author:** ![danceswithcats](https://avatars.discourse-cdn.com/v4/letter/d/9e8a1a/32.png) [@danceswithcats](https://boards.straightdope.com/u/danceswithcats)\ **Post date:** [September 2, 2006, 6:35pm UTC](https://boards.straightdope.com/t/hey-electricians-flourescent-bulbs-with-a-dimmer/370853/12 "2006-09-02T18:35:44Z")
> [@Harmonious Discord](#): > > The circuitry has to adjust the power output on a flouresent bulb. Most flouresents adjust the ouput in the unit it’s self and require the the power isn’t on a dimmer. Aparrently some are now being made with circuitry compensate and allow for an external dimmer. There are different types of dimmers nnow and I wonder if the bulbs require a certain type. Some of the new one’s don’t drop the voltage with a resistance, but pulse the power on and off for different amounts of time. Zackly. This is why you shouldn’t use an incandescent dimmer to vary the speed of a ceiling fan-the motor doesn’t like the reduced voltage it’s seeing from the dimmer. Use fan speed controls for motor loads, and dimmers _Listed and Labeled_ for fluorescent loads. Doing otherwise voids the UL of the product and as such is a NEC violation.