Does anyone know of LED bulbs with a good dimming range? I really like my Cree bulbs, but their dim range is terrible. With my automation system, an incandescent light set to 1 (out of 100) is barely visible and truly one step from being effectively off. A Cree bulb at 1, however, is more like an incandescent at 30% brightness or more.

It's been interesting reading about how LED bulbs have to handle dimming digitally through circuitry, but that means it's up to the bulb.

So does anyone know of a bulb that can dim more?

The problem, as I understand it, is that you can't "dim" an LED. You have to use PWM, which means that the LED is on for a bit and then off for a bit, and so on.

If you "dim" it too much, the flickering becomes visible to the naked eye, and that gets really annoying. So, yeah, maybe there are LED bulbs that will dim further, but you're never going to get as dim as an incandescent.

Have you tried one of the newer LED filament style bulbs? A smart bulb might allow lower ranges as well, but you'll have to dim it with a home automation controller instead of a manual switch.

There is a fundamental awfulness to the old school methods for 'remote control' of lighting based on messing with the AC waveform being fed to the light 'bulb'. This was all we had for many decades dating back to lighting control in theatres using Variacs or potentiometers,

The electronic Triac based AC 'dimmers' worked well enough with incandescent filament bulbs by chopping portions of the AC waveform away, reducing the average power delivered to the hot filament. Sometimes there was visible flicker or shimmer but mostly this worked well enough.

Then the arrival of 'transformer' powered 12 volt Halogen complicated things as the Triac devices fought with the magnetic transformers. This begat 'magnetic' compatible dimmers. Then came 'electronic' transformers and yet again fancier dimmers to manage the hacked up AC waveform in a manner that the downstream electronics could cope with. Not perfect with flickering, incomplete dimming and delayed starting being fairly common issues. CFL lamps have similar issues.

LED lighting can be so low power that it messes with the basic premise of inline Triac dimming where the dimmer itself leeches power from the current flow to the load. When the lighting becomes very low power the dimmer often cannot sustain itself without consuming a large percentage of the total power to the load. Result is incorrect dimming, flicker or other problems.

In my view the whole idea of managing lighting by messing with the electrical supply to the 'lamp' is no longer viable. The lamp itself needs to manage its own power levels and brightness and be able to accept remotely issued commands for changes in brightness. This is of course what is happening with 'smart' lights and lamps, but overall we are a long way away from widespread implementation of this approach.

Lighting is one of a few things where there is this idea that it is ok to corrupt the AC power waveform feeding the thing. We do not dim our TV or adjust the volume of the sound system by messing with the AC input.

It will be a bumpy road from where we are currently with household AC wiring to reach an intelligently configured future where the power provided to all devices is clean and uncorrupted, including those devices providing lighting.

I had not realized that the US electrical code had been changed to require AC neutral conductor in new construction switch boxes, since 2011. This will allow for more stable operation of the dimmer controller itself but does not address the underlying problem of bizarre and potentially incompatible waveforms being delivered to the downstream lighting devices. Not to mention the undesired results from inadvertently 'dimming' a non-lighting device such as a TV.

I agree with everything you guys have said. I hadn't thought about smart LED bulbs being able to dim further but that makes a lot of sense. I'll have to look into whether any of them are supported by my system.


Ugh, don't get me started. Again, this is an issue I've had to warn new home automation users about. For some reason I keep coming across people who want to automate a lamp plugged into a switched outlet, and they decide to use a dimmer switch to do this. Yes, it'll technically work...for that lamp. But you won't want anything else plugged into it and that's too hard to predict.

Lutron makes a plug specifically for dimming lamps which I came across on amazon once and thought was an interesting idea.

My house is too old to have neutrals in any of the boxes, so I'm stuck with the older style dimmer with very few choices for zwave switches. They make every LED bulb purchase an adventure.

So it is against the rules entirely to allow dimming control of a standard outlet. Only allowed with special outlets and special lamp plugs.

That would imply that you cannot legally provide dimming controls to regular outlets, regardless of whether your clients promise to not plug other things into that outlet. Liability ...

Grounds (green or bare wire, missing from really old wiring), not neutrals (white wire, always present for 110-125V outlets).

Cheers

I think he was talking about wall light switch boxes, not receptacle/outlet boxes. Often no neutral/white wire in switch boxes.

Oh no no, I wouldn't ever do this for a client. This is just when I'm chatting with automation newbies in online forums.

LED dimming is challenging. I have all sorts of LEDs in my house, in some situations even a small change like changing a bulb (like for like) can start lamps flickering, degree of dimmability is also variable.

Ours are all on trailing edge dimmer switches, we didn't go for any fancy controls. The least hassle/most reliable have been the LED tape connected to driver that we've used for "wall washing".

Is that LED 'driver' module rated for dimming?

Many LED strip 'electronic transformers' are simply regulated output 12 or 24 volt DC power supplies, sometimes simply repurposed from generic laptop or other 12 volt power packs. Not rated or intended for any sort of AC dimmer control.

In my opinion LED strip lighting should be dimmed and controlled on the DC side, not the AC feed.

I have a very basic understanding of electronics, I assume that the driver is dimmable as it does indeed dim the tape, but I have no idea what's actually in there.

On a related tangent.. We installed a basic home-centre style range hood over the gas range in our kitchen. For the first few months it used just a regular pair of PAR20 halogen bulbs for the built-in lighting.

The unit has a three-step electronic dimmer circuit for the lighting, plus "off".

After a while, we got around to trialing LED PAR20 bulbs in the same unit, carefully monitoring to see if the plastic bulbs suffered from the stovetop heat. So far so good on that front, but..

Wandering to the kitchen for a midnight glass of water, I noticed the fixture was "on", though quite dim. Turns out, it is like that all of the time when supposedly "off". There is some leakage current always flowing, never enough to illuminate the halogen bulbs, but sufficient to light up the LEDs (dimly).

So that got fixed pronto, by hardwiring a new switch into the fixture to turn it completely 100% off, electronics and all. Such a senseless waste of power.

Cheers

I have yet to find an over the stovetop vent hood that is actually excellent. Even if the lighting control was well done, the fan noise is probably an order of magnitude louder than desirable.

Three speeds; Loud, louder, and at the loudest setting modest actual airflow.

My last house I removed the built-in noisy fan from the range hood housing (it was marketed as a high end quiet model) and instead ducted it to a attic mounted Fantech exhaust fan. Routed through a Fantech inline silencer unit (rated for kitchen exhaust) between fan and range hood (with a length of flex ducting to limit vibration transmission). Fan exhaust was through the roof with a weather shroud, but could also have been eave vented.

The result was circa 600CFM exhaust flow yet one could speak in normal tones while standing right in front of the cooktop, with the fan on high.

Excellent air flow and visitors standing in the kitchen often were not aware the fan was running, let alone on high.

I forget whether I used the 8XL or 10XL inline fan for that install. Worked very well and I would do something similar again. Buy the range hood for the aesthetics and lighting, bin the supplied fan and remote mount a 'real' exhaust fan.

We have a Berbel, it was expensive but it's the quietest and most effective hood that I've seen, it has non dimmable LED lights. Very easy to degrease too.

Interesting that the spec for sound levels is given for 'stage 3' while the fan speed range goes to 4.

I didn't see any mentions of noise or sound levels in the product descriptive texts, only within the tech specs tab.

Zero-based indexing problem?

Sorry, work eats my brain sometimes.

My guess is they don't want to publicly admit how loud the exhaust fan actually is on maximum speed so they selected a slower speed for the noise measurement.

We have a Blockline 120cm, it has 3 speed settings, compared to Gaggenau/Neff etc hoods that I've seen in other peoples houses this is noticeably quieter.

Just a small update: I actually ordered a ZWave LED bulb (because my whole network is ZWave) and well, it's probably a tiny bit worse. I'm guessing this is a bulb-by-bulb issue, so I don't know if a Hue bulb can get darker. I wouldn't be surprised, since it's probably a little better made than this one.

For now, I'm going to put a 40W bulb in the "nigh light" lamp and dim it to an extremely low level. It won't be quite as low energy usage, but it'll be close. I'm basically trying to ween my son off of a night light completely, so I need to be able to go reeeeally low, and LED's just can't do it, it seems.

LED bulbs can be covered with a coating or fabric that absorbs some of the light output. Just don't clog any air venting or cooling fins. You could experiment with draping or wrapping the bulb to reduce the effective light output.

Don't do this with incandescent bulbs, of course.

The theatre lighting world used to use neutral gray and colored filter gels all the time, I imagine that sort of thing is still available.

Other Industries also have similar films. You can layer the films to multiply the light reduction.

http://www.solargraphicshome.com/Neutral_Density_Film.html

This video shows the sheet neutral gray filter material, 1:58 mark.

One "solution" to getting a dim LED bulb might sourcing an older one. The newest are quite bright. Anything more than a few years old? Not so much.

That would dim all light levels, though, so I couldn't get the bulb as bright as I might want.

I think I'll go incandescent until I don't need the light at all.

You could use some other lamp for 'bright' and the cloaked lamp for 'very dim'.

Nah, that's not what I'm about. The whole reason I got into home automation is because I really love to have even lighting throughout a room. So I spread the light sources to logical and appealing spots, then set them all to the optimum dim levels for whatever scene I'm creating. My least favorite way to light a room is to have a single lamp in one corner that's turned bright enough to do something in the opposite corner, as that lamp will be too bright at its source.

So that would mean that to accomplish your suggestion I would have to have two lamps in the same spot. I guess I could also have a lamp with two ZWave bulbs in it, one of them "cloaked." But then I wouldn't be able to use the super cute monkey lamp that we currently use as his night light

I think I'll stick with the 40W. It's not going to suck too much juice. Not at these levels.

I've gone back to the 40W bulb and it works so much better. I can set the dim level to anything, and it performs beautifully.

Now I have two more questions for you kind folks:

1- What's with the buzzing? So many of my light fixtures let off this buzzing noise that seems much more pronounced with the LED lights in them. What's going on here? It's not as bad when the light is at full brightness, but when it's dimmed it's really bad.

2- Does anyone else dislike the color temperature of a dimmed LED bulb? I feel so set in my ways, but I guess my brain just likes the additional warmth of a dimmed incandescent bulb. It looks like LED bulb manufacturers know this, and I've seen at least one Cree bulb that claims to offer that behavior. Anyone else feel this way?

That's why I hate everything but incandescent lights. Fluorescent and LED all buzz because they need some kind of transformer. Those kinds of lights can't accept the AC current as-is, it's gotta be changed somehow, either to a DC current or to some other variant of AC current. What you're hearing is the transformer. Usually a cheap-ass crappy one, because good transformers cost more than people usually expect to pay for a light bulb. Whereas incandescent lights don't need any change at all, they just take the AC directly off the wire.

Some of the more expensive LED and incandescent lights might start their life buzz-free but then develop a buzz later on as they get older and the transformers age.

In my home studio, noise floor is everything, and I can't abide fluorescent or LED lights of any kind. (Or dimmers of any kind, which often induce their own buzz, either audibly or injected into the house current so that it shows up in the audio recording). What I don't understand is what audio recording studios (including my own) are going to do in the future when incandescent bulbs no longer exist.

Maybe candles?

Thanks Tony. That makes sense. I wonder, then, why the incandescent bulbs in my bathroom vanity also make that buzzing sound. They are also dimmed, but the buzzing comes from the fixtures and not from the switch. Is that still the dimmer producing that buzz?

If that's so, I wonder why all sorts of combinations in the rest of my house don't have this problem. I have LEDs and incandescents on dimmers and lamp modules elsewhere and they don't make this noise...

Hum, buzz, induced noise - it is possible to control and isolate electrical noise, but it requires willingness to make changes.

A decade or so ago I listened to an engineer describe how he designed and built a sound recording studio with the specific objective of eliminating electrical noise. It was successful, and he related a story about a guitarist that came in to use the studio. He was accustomed to adjusting his amp until he could just barely hear the background buzz. Powered up in the studio, he was concerned that his amp was not working. He turned the volume up, then turned it up some more. No buzz or crackle, it seemed like it was off. Turned it up some more. Still quiet. Someone suggested he try playing something, and the amp responded at huge volume. There just was no AC hum, it was completely clean sound.

Electrically noisy equipment can be tamed and silenced. Shielding, well configured grounding and electrical isolation techniques can be very effective.

As I posted previously, dimming CFL and especially LED lighting by messing with the AC waveform (aka 'dimmers') is bass ackwards. Provide clean power to the lighting and have the lighting itself control brightness. Use high quality DC electronics for the LED dimming and control.

The glowing filament inside an incandescent bulb is an electromagnet. When the AC current flows the filament develops an oscillating magnetic field, 60 magnetic cycles per second.

With full brightness the AC current (not voltage, current) through the filament ramps smoothly in a sinusoidal manner. Sometimes a bulb filament will vibrate sympathetically with this alternating magnetic field even at full brightness but generally the sound is inaudible.

If you bring a strong magnet near the bulb surface you may be able to see the filament vibrate visibly.

When the power to the bulb is 'electronically' dimmed the previously sinusoidal AC current waveform becomes bastardized. The magnetic field now jolts and collapses repeatedly, 120 times per second. The glowing filaments can vibrate sympathetically and conduct the vibrations to the lamp base and the fixture.

Do the lamps that buzz when dimmed have a filament design that zigzags or loops around inside the bulb? Sometimes that can magnify the magnetic resonance effect and become more audible.

The bulb construction is such that it acoustically conducts the filament resonance more than a different brand or bulb filament design. If you find a different bulb that dims with less sound, change the bulbs.

Curiously, here is a patent describing the magnetically indused vibration of the support wires for the filament. I found this interesting; The frequency of the noise emitted by the lamps was in the range of 4,000 to 15,000 Hz.

That would be very much in the range of human hearing, but at the high end.

Tips from around the Internet;
Lutron Lamp Debuzzing Coil (LDC)

http://forums.mikeholt.com/showthread.ph...8921#post958921

I haven't disassembled an LED bulb to look, but it's really doubtful they use such expensive (copper) and space consuming tech. More likely a simple diode or similar.

The cheapest/simplest way I can imagine to build an LED bulb from scratch, would be to just insert a power diode in series with about 80 LEDs (120V operation), assuming each LED drops 1.5V from input to output. Adjust the quantity if the drop is different.

EDIT: actually, the power diode isn't needed, since each LED is a diode already!

Now that bulb will flicker at 60HZ, so it could be improved with a full-wave rectifier, aka. four diodes instead of one, so that it flickers at 120HZ instead. Add a nice capacitor or two to blur the flicker to imperceptible levels.

Commercial bulbs are undoubtedly fancier than that. I really should sacrifice one to the gods of curiosity some day soon!

The two most common versions I've seen are
1) proper switchmode supply (controller chip and inductor) operating at a much higher frequency than the mains.
2) series inline capacitive dropper limiting the current like a resistor, but with an almost 90 degree phase angle between voltage and current to avoid much real power lost,followed by rectifier bridge and smoothing cap. Resistors to limit inrush current and to discharge caps - mainly in the cheap Chinese ones.

For looks inside various LED bulbs I can recommend BigClivedotcom on youtube

Edit: He just posted on dimming LEDs with mains dimmers - https://www.youtube.com/watch?v=fWh2obSY0dQ

There's always the option of using 12v DC LED's in series, and then power them all via one good-quality transformer. (the same system that is used for halogen spots) Or use a micro transformer of good quality per light, but then you need adequate space behind the ceiling to tuck it away.

Thanks for all the information, but my takeaway after reading all of this and looking at other sources online and trying some things out is that it just depends on the equipment.

In our master bathroom we have recessed lights and vanity lights. The recessed lights just had a random selection of bulbs that the contractor put in there and I never bothered to replace. Some regular light bulbs, a BR30, and one vanity bulb for some reason. These didn't buzz. Our vanity, on the other hand, consists of two fixtures with two bulbs each, and were regular 60W incandescent bulbs, and those bulbs buzzed like crazy when dimmed.

These lights are all controlled by the same two dimmer switches, and had the same behavior when being controlled by their previous, cheaper dimmer switches.

So last night I replaced all the bulbs in the bathroom with Cree LEDs. Standard A19 bulbs in the vanity and BR30's in the recessed lights. The result is that the vanity doesn't buzz (or has the faintest buzz that I don't think I'd notice if I weren't listening for it in a silent room), and the recessed lights are buzzing terribly. It's louder than any light buzz I've experienced.

I think I'll be returning the BR30's and trying another brand. It's too bad, the Cree bulbs are starting to look really sharp these days. I might try one of the ecosmart bulbs and then maybe a more expensive one and see which one is the winner.

Regarding color temps when dimmed:

I find it strange that all my older Cree bulbs give me a more incandescent behavior when dimmed, and the newer ones perform more like you'd expect from an LED.

Perhaps you meant to say 'in parallel' ?

Yes. That. I always mix those terms up.

An update:

I went out and bought two brands of BR30 bulbs. I picked up a 6-pack of Ecosmart (Home Depot brand, I believe) for $30 and a 3-pack of Philips for [I believe] $21.

The important thing about the Philips bulbs is that they're advertised as having a "warm glow effect." It's just saying that it mimics the effect of a dimmed incandescent bulb. That sounded like what I was looking for.

Long story short, I hated the Ecosmart (the color was just not great), and I loved the Philips. The warm dim was subtler than I expected, and just what I was looking for. I still feel silly about it, but it's what I'm used to and my wife preferred it to, so that's what I'm going with.

The only problem was the price. At $21 or more for 3 bulbs, it was going to be an absolute fortune to replace all my BR30's (I have a ton of them in my house - around 35 at last count). Fortunately, Amazon came to the rescue once more. There's a seller offering 24 bulbs for $135, coming out to about $5.63 per bulb, which is pretty good. My favorite thing about it is that it's clearly a box that's intended for a Home Depot show room, because it ships as a display case, including the standup to advertise the bulbs, with pretty clear HD styling.

At that price, I'm actually considering buying a second pack to fill in the remainder of the cans, then having some on hand for future recessed installs, or I could sell the rest at my upcoming yard sale and come out way ahead of buying the 3-packs.

Oops, I forgot one last thing:

I put Philips warm glow BR30 and A19's in all the fixtures in my master bathroom. No buzzing! I don't know if there's just something about those Cree bulbs, but the difference is drastic.

The delta is about $33 between the $135 for 24 display pack and 8 packs of the $21 three pack, by my math.

Delta of $1.40 per bulb is not quite a fortune. Diner out, perhaps.

Thanks for posting the results. Will be handy if others are looking for that form factor in LED dimmable light bulbs.

True, but one requires me to go to Home Depot, load 8 packs of bulbs into a cart, scan them one by one (because they never man the checkout lanes at my store), and drive them home where I unload all the bags.

Or, Amazon Prime delivers a big box of 24 bulbs to me in two days, I save $33 (and get some dinner), and I don't have to do anything. Winner!

I've never been a penny pincher (even when I probably should have been), but saving $33 here and there adds up tremendously.