Dimming LED and CFL light bulbs?

[valent]

We use only CFS lights in our whole flat because we like to use green technologies and save energy, but we would also like to have dimmed light some time.

Is it possible to dim LED and CFL light bulbs? How? Are there some special ZWave dimmer switches? Is ti possible to use ordinary dimmer and modify it somehow? Or just use ordinary incandescent light bulbs?

[phenigma]

Most commercially available led replacment bulbs and standard CFL bulbs are not dimmable.  Dimmable CFL bulbs are available, although at a premium of about 5x the cost of a standard CFL bulb.  There are likely dimmable LED replacements available as well but I havn't seem them on the shelf yet.  With the cost of dimmable CFL bulbs I use regular incandescent bulbs where I want dimming.

J.

[maverick0815]

check this one out http://www.leds.de/ they are providing dimmable led arrays...but the price....

[twodogs]

I'm with phenigma. I did a lot of research on this a while back and wrote it down for my green renovation blog. Maybe too much information, but...

Info on dimmers and lighting types:

A filament lightbulb works as electricity flows through a thin wire, causing it to heat up and glow. The hotter a wire gets, the more it resists the flow of electricity. So a cool light bulb draws a lot of current when you first throw the switch, then the current slows and stabilizes when the bulb reaches operating temperature. This initial current rush explains why bulbs typically burn out at the moment you hit the switch. Electronic dimmers like those used in home automation systems work by rapidly interrupting the flow of electricity. This reduces the current through the bulb and dims the light.

A fluorescent light is basically electric current flowing through a gas. Unlike a filament bulb, the gas initially presents high resistance to the flow of electricity, but the resistance goes down when the bulb lights. The decreased resistance allows more current to flow, and the increased current through the gas decreases resistance even more. To prevent a runaway condition that could trip your circuit breaker, a fluorescent light employs a “ballast” to regulate current flow. The ballast is essentially a transformer that uses coils of wire to establish a magnetic field. It takes energy to create the field, and that creates just enough resistance to establish the proper electrical flow through the light.

A low voltage light normally uses a transformer to reduce your 120V household current to 12V. As 60Hz alternating current flows through the primary coil of the transformer, it causes an alternating magnetic field. This fluctuating magnetic field induces electric current in the secondary coil of the transformer. The voltage is reduced to the desired level by using fewer windings in the secondary coil.

Electronic dimmers have difficulty driving inductive loads like ballasts and transformers. The problem is that ballasts and transformers are tuned to the smooth 60Hz alternating current found in your home. The dimmer,  by chopping up the flow of current, plays havoc with the magnetic field in a ballast or transformer. Insteon tech support told me their dimmers might work with some transformers, but others will cause dangerous overheating and/or potentially destroy the equipment.

[valent]

Found this article:
Dimmer Switches: A Bad Idea for CFLs or Incandescents
http://www.treehugger.com/files/2007/04/dimmer_switches.php

[trentend]

I went through the same research curve as the other respondents.  Ultimately I decided on a non-dimming solution.  Where we want to create lower lighting conditions we have power sockets in each room, switched seperately from the main power sockets.  To these we connect lamps with lower power  energy efficient bulbs.  We create a range of lighting scenes with a combination of the main lights and lamps - all controlled by our KNX switches and lighting scenes and all using energy efficient bulbs.

KNX dimming controllers are good to use with traditional light bulbs as you can gradually ramp up the power on switch on to reduce wear on the bulb and increase life.  Presumably it's also the case with other dimming controllers.

[totallymaxed]

We use only CFS lights in our whole flat because we like to use green technologies and save energy, but we would also like to have dimmed light some time.

Is it possible to dim LED and CFL light bulbs? How? Are there some special ZWave dimmer switches? Is ti possible to use ordinary dimmer and modify it somehow? Or just use ordinary incandescent light bulbs?

There are LED & CFL ligh bulbs now that can be dimmed - but they are expensive...3-4 times the cost of the standard LED or CFL bulb.

You can get ZWave load controllers that will handle Switch Mode Power supplies used in many 12v low-voltage lighting installations - Merten have several for example.

All the best


Andrew