Minimum dim level

[gengen]

One of the issues I'm looking closely at for my new HA project is the minimum dim level, especially for the lights in my bedroom. Ideally, I'd like lights to ramp up very slowly (over perhaps 1/2 hour) to create an "artificial sunrise" which helps me wake at a certain time regardless of the time of year. The problem is that most dimmers have a minimum dim level below which they cannot control, this is especially true when it is very dark and your eyes are accustomed to the darkness. This means that the lights will suddenly "pop on" to a low, but noticable level, which I would like to avoid.

Environmental Lights has a nice white paper which describes various aspects of dimming LED's along with a compatibility chart which was last updated in October, 2012.

http://www.environmentallights.com/files/documents/How_to_Choose_the_Best_Dimmer_for_a_bulb.pdf
http://www.environmentallights.com/files/documents/dimmer_compatibility.pdf

Although they list a wide variety of bulbs, their selection of dimmers is somewhat limited.

Moreover, many dimmer manufacturers don't seem to list the minimum dimming level of their devices in their own specs.

Of course, much of this depends not only on the dimmer, but also on the type of bulb. Good old incandescent bulbs may be the easiest to dim but they are also energy hogs.

Does anybody on this board have good or bad experience with various dimmers and bulbs and how low they can go without being completely off?

 

[jhdale]

I have to admit the lights in the bedroom are the one place I still have incandescents, exactly because I start with a slow on (8 minutes).

>how low they can go without being completely off?

Most of them can actually go lower if you start on and dim, but have a higher threshold if you start off and brighten, which is what matters here.

I just did a test right now with a Philips AmbientLED (the funny orange ones, http://www.usa.philips.com/c/energy-saving-light-bulbs/ambientled-12.5w-a19-soft-white-dimmable-046677409906/prd/en/ ) which has great light and dimming in general. It actually turns on when I set it to 1%, but it's a lot brighter at that level than an incandescent would be. (Also, not certain whether it comes on immediately at that level or takes a second.) With a very slow ramp, you also see it "step" up from level to level. On a fast ramp, it seems perfectly smooth. I could try it with the L-prize bulbs too if you want.