Dimmer switches are an excellent addition to any lighting design plan for their ability to control the mood of any space in the house. Light dimmers enhance the aesthetics of interior environments, adding stunning dynamics to a room by allowing you to spotlight some spaces and mute the lighting in others, resulting in a layered effect.
Imagine a dinner party with five layers of light contributing to the sense of drama in the room or watching a film in the lounge room with lights dimmed low enough to eat without impacting the viewing or dining experience.
Using light dimmer switches in an indoor or outdoor space not only helps you control the brightness in the space, but also improve its aesthetic appeal. Very importantly, dimming helps you save energy. Dimmers range in size from small units to suit domestic light switches to high-power units used in theatrical and architectural lighting installations.
A dimmer switch allows the user to adjust the intensity of the light by emitting a pulse-width modulation signal that controls the voltage and current going into a light. The dimming motion enables you to increase or decrease the intensity of the light.
Image: Buzzi & Buzzi, GENIUS CURVE
All LED light fittings are dimmable. Lighting engineers only need to ensure that the dimming signal is compatible with the driver that is supplying power to the light. The most popular dimmer switch signals on the Australian market today are phase signal (leading edge or trailing edge)/ DALI/ 1-10V.
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Dimming methods
Resistive dimmers
There are two types of resistive dimmers: leading edge and trailing edge.
Leading edge is the most common type on the market and can dim standard incandescent lamps, low voltage transformers powering low voltage 12V lamps and constant current dimmable LED drivers.
Leading edge dimmers are rated by the maximum recommended wattage it can dim. Overloading the dimmer can cause damage to the dimmer. This type of dimmer also dims constant current 230V dimmable LED drivers.
Trailing edge is less common and more expensive, and incorporates added technology and features. These dimmers are suitable for wire wound transformers, standard incandescent lamps, mains voltage halogen lamps and dimmable LED lamps. A dedicated trailing edge dimmer (as opposed to a Universal type dimmer) is better suited to LED light fittings and gives very stable control of the light fittings on any specific circuit.
Additional features that can be included in a trailing edge dimmer are soft start, smooth control, silent running and multi-method dimming functions. These features can all assist in extending the life of the lamps.
This dimming option gives you less control of individual lights in a cluster. In a room of 6 downlights, it is less expensive to set up and run. There are also a wider range of fittings that are compatible with that signal, resulting in less expensive fittings and most importantly, less expensive future replacement costs when the light globes burn out.
Inductive dimmers
These are located on the secondary side of a low voltage or lighting scheme. Inductive dimmers are rated by voltage rather than wattage. These are not suitable for home settings and not available in the retail market.
DALI
Digital Addressable Lighting Interface (DALI) is a trademark for network-based products that allow you to control all your light fittings independently. It is generally used in conjunction with a home automation system or lighting control system. The programmer gives each light fitting a specific address; therefore, each lighting fitting is controlled independently of the other.
For instance, if you have 4 downlights in your bedroom, you could control each of those 4 downlights independently. By comparison, when using a lighting control system with phase leading edge or trailing edge dimming signal, all the lighting fittings on the one specific circuit are controlled together. All 4 fittings are either off or dimmed together.
Fluorescent light dimmers (1-10V)
Dimming fluorescent lamps is complex and requires a high frequency analogue 1-10 volt regulated ballast. There are some compact fluorescent lamps available on the market that will work with this type of dimmer.
Please note not all lights dim the same – different lighting brands perform differently. Some ‘dimmable’ lights will not dim much and can only dim in a 3-stage stagger, while others will dim to almost no light output with much gradation. Some will have a smooth change in brightness while others have quick jumps in their brightness as they are dimmed. The variation in performance between models and brands is generally quite significant.
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Do dimming lights save energy?
Light dimmers save energy by reducing the flow of electricity to the light, allowing lights to operate with lower power input. Dimming lights also extend the life of your light source.
By reducing the amount of electricity being sent to a particular light fixture, dimmers help lower the electricity expenditure for that fixture by 40% to 90%, depending on the dimming level.
Built-in dimmers
There are two types of built-in dimmers: rotary and pushbutton. Though these are obviously different styles, both dimmer switch types can integrate beautifully into a wall.
While a rotary knob dimmer needs to be turned to select the light intensity, a pushbutton dimmer requires you to press the button until you reach your desired light intensity. Some pushbutton dimmers alternate in their operation (brightness increases during the first long press, dimming occurs during the second long press). Other pushbutton dimmers reach a specific percentage of brightness.
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What are light dimmer location options?
Dimmers typically come in three location options:
- Single-pole dimmers are designed to provide dimming control from only one location.
- Three-way dimmers adjust the lighting levels of your space from one location, but are installed with three-way on/off switches allowing you to turn the lights on to the dimmer level from different locations.
- Multi-location dimmers are typically paired with accessory dimmers that allow you to fully control and dim the light output from multiple locations.
Image: Melogranoblu, Diapason A Wall Light
Internet-enabled dimmers
There are manual and internet enabled dimmer switches that allow you to adjust energy output and light intensity from your phone in the form of an app. The more expensive dimmer switches often include features such as a sleeker design and integration with smartphones.
Image: VeniceM, Rectus Floor
What are the compatibility issues with dimmers?
Phase signal dimmers can have issues if the load on a specific circuit (the number of fittings on that specific circuit and, therefore, the power draw of the circuit) is very low. Low power draw causes light flickering. Light flickering is resolved by the use of a load correction device that is retrofitted by the electrician to artificially increase the load on that specific circuit, thereby, stabilising the power and eliminating the flicker.
When converting old halogen lights into LED fittings, legacy technologies present a major challenge. For instance, a typical halogen downlight has a 35W or 50W halogen globe and iron core transformer. The technology uses too much energy to deliver the light source. Modern LED downlights only draw 6W per fitting.
When installing an LED light fixture in a halogen fitting, the load on the circuit is significantly reduced. Transformers and dimmers need to be changed to the new technology. Do not mix dimming circuits from different manufacturers as you may get flicker, stuttering dimming and rushed dimming problems.
Image: Fabbian, Lumi Wall
