Understanding LED Lighting

Smithie Lighting has compiled this simple guide to help our customers to understand the basics of LED Lighting, it has been created to assist you in making the right purchasing decisions.

LED lights offer up to 90% energy savings compared to traditional halogen or incandescent bulbs, they also have a vastly superior life span – lasting 10,000's of hours compared to a traditional bulb which may last only 1,000 hours.

Even comparing LED bulbs with the older style CFL low energy lighting there are clear advantages – as you flick on the light switch, an LED light will instantly offer full illumination, while the CFL would still be warming up. LED lighting can also be manufactured to produce a range of different colour temperatures and quality of light (known as colour rendering).

While the benefits of LED lighting are now fairly well recognised, what a lot of consumers don’t understand is that LED lights vary massively in quality.

The majority of LED lighting manufactures all promise unparalleled performance, in terms of lifespan and the quality of the light the bulb produces, but they can’t all be right can they?

Quality is Key

With LED lighting, as with many products, quality is absolutely key. Whilst you may be able to find an LED in the shops for £3 a bulb, chances are that it will produce poor light and pack up within the year. We recommend spending a little more on a quality bulb and getting one that will last for years, give off a quality light and save you money.

Heat Dissipation

One of the most telling aspects to a LED bulb when it comes to quality is how well the bulb dissipates heat.

A common misconception is that LED bulbs don’t get warm, however this isn’t the case. They don’t get nearly as hot as incandescent bulbs, but since power goes into the LEDs, they do produce heat and this must be drawn away from the LEDs.

Unfortunately LEDs can’t radiate this heat away in the same way as an incandescent bulb – instead, the heat needs to be drawn away from the LEDs by a heat sink normally located in the bottom of the bulb. The heat sink absorbs the heat produced and then dissipates into the surrounding environment.

If the heat sink doesn’t fulfil its job correctly, the LED will overheat and most likely burn out. So a badly designed heat sink will be detrimental to the lifespan of the LED bulb, and efficient thermal management is really important to ensure that the LED bulbs last as promised!

There are lots of different designs for heat sinks, which is why the appearance of LED bulbs changes so much between brands. You may be familiar with the metal fins on some LEDs – higher end LEDs will have aluminium fins or ceramic heat sinks. The ceramic fins in many cases can be more effective than any metal heat sink, since they possess lots of tiny pores, which provide an even greater surface area to dissipate the heat from compared to metals. Ceramic heat sinks have a very low thermal capacity, but the highest surface area to maximise heat loss into the surrounding environment.

Chip Set

Whilst heat dissipation is important – the chip used to convert electricity to light is also really important.

A poor chip will generate more heat, and will therefore not last as long. Better bulbs will use chips from better manufacturers, which generate less heat and convert more energy to light – it kind of goes with out saying you get way you pay for, and this is 100% true with LED lighting, if you buy a GU10 for £3, you should probably question the quality of the chip set used.

Power Driver

The driver regulates the power entering the LED’s, ensuring that the bulb operates optimally and does not overheat. In an MR16, this device will be found in the light switch or in the fitting, because the bulb does not have an inbuilt driver. GU10s have an inbuilt driver and therefore do not need an external device.

In all honesty, if you do decide to make the switch to LED bulbs, we recommend ignoring MR16 spots completely and just installing GU10s even if you have to change the fitting. To swap an MR16 for a GU10 will cost you less than £25 per bulb (including the new GU10 fitting), which you will pay back in just a couple of years based on the energy savings.

Colour Temperature

Unlike traditional incandescent and halogen bulbs that tend to produce a warm white light, LED lights are available in many different colours – this is known as the colour temperature of the bulb. To replicate the colour temperature produced from a halogen GU10, you would need to opt for a warm white / daylight coloured bulb. If you prefer the cooler light often associated with office spaces, then you would probably prefer the cool light bulbs. The diagram below shows the different temperatures:

This is an example of how the different temperatures may look:

Lumens 

Lumens are a measure of the total amount of visible light (to the human eye) from a lamp or light source. The higher the lumen rating the “brighter” the lamp will appear. Gone are the days when you can compare the wattages of bulbs to distinguish which bulb will be brighter as this incorrectly linked power consumption (Watts) to light output. The reason for using lumens to measure is that a 50w halogen GU10 spotlight can be replaced with an equivalent 5w LED GU10 spotlight – the lower wattage is the main reason households can achieve such massive energy savings from LED bulbs – you just need to ensure that the lumens are similar between the two types of bulb to make sure you are going to get the same sort of light intensity.

Colour Rendering

Colour Rendering is the ability for a light source to give a true reflection of the colours of the object it is illuminating. That is a bit of a mouthful, but essentially the higher the colour-rendering index the closer to daylight the bulb is (daylight portrays objects perfectly – it has a CRI of 100%).

If the lights are used a lot, then you want to go for an LED bulb with a CRI of 80+, however if the bulb is just used for emergency lighting for instance it can be sub 80. The higher the CRI of the bulb, normally the more expensive it will be to buy, but if you are into painting for example, you will want to pay more to ensure the bulb has a CRI of 90+ to ensure you are getting a more accurate view of what you are painting.

IP Rating

IP Ratings or Ingress Protection Ratings are used to define how effective the sealing levels are at keeping out foreign bodies. The first part of the number indicates the degree of protection from moving parts and the protection from solid foreign bodies. The second defines the protection level from various forms of water.

First Digit (solid protection)

0 - No special protection.
1 - Protection from a large part of the body such as a hand (but no protection from deliberate access); from solid objects greater than 50mm in diameter.
2 - Protection against fingers or other object not greater than 80mm in length and 12mm in diameter.
3 - Protection from entry by tools, wires etc, with a diameter of 2.5 mm or more.
4 - Protection against solid bodies larger than 1mm (eg fine tools/small etc).
5 - Protected against dust that may harm equipment.
6 - Totally dust tight.

Second Digit (liquid protection)

0 - No special protection.
1 - Protection against condensation.
2 - Protection against water droplets deflected up to 15° from vertical.
3 - Protected against spray up to 60° from vertical.
4 - Protected against water spray from all directions.
5 - Protection against low pressure water jets (all directions)
6 - Protection against strong water jets and waves.
7 - Protected against temporary immersion.
8 - Protected against prolonged effects of immersion under pressure.

An IP rating of 65 therefore signifies the product is protected enough for use outside.

Beam Angle

The final thing to consider when buying LED bulbs is related to the beam angle. This is something that you might not have considered before, but if you are swapping from halogen spotlights over to LED’s, it’s actually quite important.

Halogens tend to produce a wider angled light than is suggested on the pack, so simply swapping a 35 degree angle bulb for the equivalent LED will create a very narrow angle of light. If you have a low ceiling or need an even spread of light across the room, it is really important to look for a wide 100+ degree angled LED. If you have high ceilings or need a narrower, focused light, you should go for a lower angle beam.

Eco Friendly

LED lights are up to 90% more efficient than traditional lighting such as fluorescent and incandescent lights. 95% of the energy in LEDs is converted into light and only 5% is wasted as heat. This is compared to fluorescent lights which convert 95% of energy to heat and only 5% into light! Less energy use reduces the demand from power plants and decreases greenhouse gas emissions.

LED lights contain no toxic elements. Most offices currently use fluorescent strip lights which contain noxious chemicals such as mercury. This will contaminate the environment when disposed of in landfill waste.

A longer life span means lower carbon emissions. LED Lights last a lot longer than other types of lights, reducing the requirement for frequent replacements.