Defining ‘Dimmable’: what should end-users expect from dimmable LED lighting?

Andrew Wilson at Varilight calls for greater clarity around the term “dimmable” when it’s applied to LED lighting. With a diverse array of driver technologies, only the best LED dimmers in the market can reliably deliver on the promise made by the “dimmable” label. This is not always made clear by lamp manufacturers, leaving wholesalers with a role to play in pointing customers in the right direction.

Lower prices have encouraged an even greater uptake of LED lighting, and with greater affordability, many installers are opting for dimmable LED lamps. However, it’s important to note that “dimmable” doesn’t usually equate to “dimmable with any dimmer”.

Experience of a patchy performance with an unsuitable dimmer can damage the reputation of dimmable LED lighting and lead to its ability to perform as a genuine replacement for incandescent or halogen lamps. So it is clearly in the interests of LED lamp manufacturers to assist customers in choosing a suitable dimmer and many have published guides on their websites.

Unfortunately there are other lamps on the market where such guidance is lacking or out-of-date. So it is worthwhile for wholesalers to familiarise themselves with some general rules so that they are in a position to offer advice to installers themselves.

It’s becoming more widely understood that traditional dimmers are not well-equipped to deal with the demands of most LED lighting. One reason for this is that an LED load will quite often fall below the minimum wattage requirement of a dimmer that was designed to control incandescent lighting.

In response to this some dimmer manufacturers have designed “low load dimmers” which can cope with the low wattage of a typical LED lighting load. However, without additional features, standard triac-based, leading-edge dimmers do not have the versatility to contend with many LED loads.

This is compounded by variations in lamp specifications within what remains a largely unconsolidated market, with many approaches having been taken to designing the electronics that make up the LED driver technology within the lamp.

Versatile LED dimmers

Unless a common dimming standard can be agreed upon by lamp manufacturers on the characteristics of their drivers, versatile LED dimmer switches, capable of both leading-edge and trailing-edge dimming with a programmable minimum (and, ideally, maximum) brightness setting, will remain a requirement if end users are to get the best results from dimmable LED lighting.

Not only do the best LED dimmers in the market offer such programmability, they also have the ability to “learn as they dim” to overcome any glitches they encounter across the full brightness range, delivering a dimming performance that matches up to customer expectations.

For those on a tighter budget, intelligent LED dimmers that offer only leading-edge dimming are also available. Whilst these cannot offer the same versatility without the option to switch to trailing-edge dimming, if they offer additional features, such as an adjustable minimum brightness setting, then they can perform well, as long as installers choose lamps designed for leading-edge control. If this is not made clear on the packaging then guidance might be offered on the lamp manufacturer’s website.

A further complication can arise if a customer chooses a touch-control or remote-control LED dimmer to use with dimmable LED lamps. Some lamp manufacturers have not included provision for dimmers of this sort, which need to draw a small current to maintain their memory.

Unless this is taken into account at the design stage then some LED lamps can remain illuminated, even when the dimmer is switched off. Fortunately, load regulators, which can prevent LED lamps from glowing when the dimmer is off, are available on the market to fix issues like this.

Whether installers are undertaking a project that includes dimmable LED lighting, and looking for a wiring accessory manufacturer that offers a complete solution, or simply upgrading a customer to LED lighting, the demand for LED dimmer switches is on the rise.

Not only does a suitable dimmer switch contribute to the ambience of a lighting scheme, it can also enhance its energy-saving credentials. Informed wholesalers who can recommend reliable dimmer and lamp combinations stand to benefit from upgrading customers to dimmable LED lighting.