Less Is More: Saving energy with lighting dimmers

As the market and economy are aiming toward a green evolution, dimmers are also evolving to accommodate the growing trends with CFLs and LEDs. As the government passes bylaws to change from inefficient incandescent bulbs to low-consumption CFL and LED replacements, lighting control manufactures are struggling to overcome the challenges of effectively dimming CFLs and LEDs.

LEDs
LED technology has come a long way since a few years ago, and it has become much easier to be dimmed. Since they typically involve the use of a driver, there are almost no standard dimmers that will work 100 per cent of the time. Dimmers are not designed to properly control the low load of LEDs, and can cause the driver to fail or result in undesirable flickering.

The first generations of LED bulbs and fixtures were not dimmable due to the inability to control the extremely low 12-V loads in the circuit. Many manufactures have now been able to produce dimmable drivers that will work on most electronic low-voltage dimmers. One should consult with the supplier for tested compatibility dimmers.

Lamp dimmers
Aside from wall-box dimmers, there are also lamp dimmers that can be used to help create ambient and desirable illumination. Lamp dimmers function the same as wall-box dimmers—they can be employed on portable lamps that use 120-V incandescent and halogen bulbs. Any low-voltage or LED portable lamps may not function properly because of possible transformer and driver incompatibility.

The innovation of dimmers has provided families with convenience, comfort, and peace of mind. Traditional standalone dimmers are now available as a system that can control entire rooms or a home at the touch of a button. Additionally, occupancy sensors integrating auto on/off are now incorporated into dimmers for convenience. Homeowners and facility managers do not need to worry about leaving the lights on—the occupancy sensor can be set to turn off when a room becomes vacant for a long period, as well as being able to set to a desired light level when on.

Dimmer disadvantages
As incandescent or halogen bulbs get dimmed, a continuous buzzing noise can become audible, or sometimes a combination of flicker and noise together. The buzzing can be caused by the filament of the bulbs vibrating as the level of dimming increases on the device.

Normal AC currents fluctuate gradually; the chopped-up current from a dimmer switch, on the other hand, suddenly jumps in voltage whenever the TRIAC becomes conductive. This sudden shift in voltage abruptly changes the magnetic field, which can cause the filament to vibrate, resulting in the buzz many people hear. This can be reduced by trying a different bulb brand, as different manufacturers may produce the bulb’s filament slightly different from each other.

CFLs and LEDs do not provide the same full dimmable range as halogen and incandescent bulbs. Dimmable CFLs have the capability to dim down to 10 to 30 per cent, and both CFLs and LEDs can take some time to turn off when the dimming slider reaches the bottom. The technology of these bulbs makes it difficult to achieve a desirable level since they cannot be effectively dimmed to low levels. Progression on dimmer compatibility with CFLs and LEDs are constantly improving, and bulbs are becoming a more reliable form of incandescent alternative source.

Conclusion
Dimmers can provide a better solution to enhance home appeal. A combination of various switches in a single room can ultimately create lighting effects for every occasion. Family rooms and living rooms can achieve low-ambient lighting for relaxation in the evening, and can also have maximum lighting when needed for cleaning and entertaining if desired.

Dimmers can also be specified in commercial applications to help achieve the desirable lighting conditions. Retail spaces such as restaurants use dimmers to achieve a transition from daytime operations to evening dining atmospheres. Factories and businesses use dimmers for nightly security purposes. Any space with lighting can be a potential site to use lighting controls to achieve pleasing results and receive benefits for energy cost savings.

By allowing different lighting fixtures on separate dimmer switches, a comfort-level lighting environment can be easily achieved. Most rooms do not need 100 per cent of the lighting when the room is occupied; when dimmed 20 to 40 per cent, most activities can be carried out just as well.

Consideration should always be given when budgeting for renovations and new homes. The cost-effectiveness of each dimmer will pay off in  the long run when energy and maintenance savings are realized.

Michael Liu is the showroom manager for Royal Lighting. He has been in the lighting industry for 11 years. Liu can be reached via e-mail at mikey@royallighting.com.