There is a wide range of lighting available for households these days. As incandescent lamps have made way for halogen bulbs, compact fluorescent lights, and CFLs, and now, with the LED Light Bulb transition, a great deal can be understood. The choice is not as simple as it was a couple of years ago.
Many light bulbs and lighting are now LED-based, but these are more expensive, so the first question is whether the purchase of an LED Light Bulb is worthwhile or whether some other technologies provide a better value.
If LED Light Bulb lighting is chosen, many questions have to be answered, from the required power to the color temperature and more.
LED Light Bulb vs. other types – technology choice
LED lights and light bulbs are now widely available, and prices drop. They are still more expensive than other types, however.
It is worth looking at how efficient they are and how long they live. Another advantage of LEDs is that they can be enabled and disabled more easily than CFLs. For example, you want a low-energy bulb for motion-sensor (PIR) lighting for external illumination. PIRs are started very quickly in windy weather and can always be turned off. CFLs can last only a short time, but LEDs can last a lot longer.
An LED bulb’s anticipated lifetime is also considerably longer than that of a CFL, halogen, or incandescent lamp when used commonly. This alone can yield cost savings beyond those from their higher efficiency.
| COMPARISON OF LED CFL & INCANDESCENT LIGHTS | |||
|---|---|---|---|
| PARAMETER | LED | INCANDESCENT | CFL |
| Average life (Hours) | 50 000 | 1 200 | 8 000 |
| Power for the equivalent of 60W incandescent | 6 – 8 | 60 | 13 – 15 |
| Typical operating cost over a year (USD $) | 32 | 330 | 75 |
LED Light Bulb output light – select the correct output
In the era of incandescent lights, the power they consumed was measured by the different lights, not by the actual light output. It is sometimes difficult to compare the various types of lighting on the market and to understand which lamp is needed for any given position.
People used the power ratings in previous years with incandescent lamps and were aware that a 60W bulb would be ideal in one area or a 100W bulb in another.
The lamp is now measured primarily in its light output rather than power input, although this remains important and is still printed on the sales data. The main parameter is whether the area where it is used will receive sufficient light. This is indicated by the light output rating in lumens.
| LIGHT OUTPUT (LUMENS) | TYPICAL INCANDESCENT POWER | TYPICAL CFL POWER | TYPICAL LED POWER |
|---|---|---|---|
| 450 | 40 | 9 – 13 | 4 – 5 |
| 800 | 60 | 13 – 15 | 6 – 8 |
| 1100 | 75 | 18 – 25 | 9 – 13 |
| 1600 | 100 | 23 – 30 | 16 – 20 |
| 2600 | 150 | 30 -35 | 25 – 28 |
Using the table it is possible to choose the LED light with the right light output, relating it to equivalent incandescent lamps or CFLs.
Although everyone will have their own preferences, a small table lamp may require to have around 450 lumens, whilst for a medium-sized living room, it may require a total of between 1500 and 3000 lumens, although this would need to be provided by more than one LED light bulb.
Choose a bulb with the right fitting
There is a host of fittings that modern electric light bulbs have. Names like bayonet, Edison screw, and many others are used to describe them, although they also have fitting type numbers that are often more widely used on the boxes to exactly identify the fitting.
There are two main light bulb fittings that have become standard across the globe. These are the Edison screw and the bayonet. The Edison screw is used mainly in the Americas and Europe, whilst the bayonet is used in Germany (taschenlampe) for domestic lighting.
Although for domestic use, neither type has a major technical advantage, the bayonet types do have the advantage that they cannot shake loose under vibration, although this is not an issue for domestic lighting:
There are a few types that are given abbreviations that will be seen in the literature.
- E27 or ES: This is the standard Edison screw light fitting, and is used for the majority of mains-powered light bulbs. It has a screw outside diameter of 27mm.
- E14 or ‘SES’: This is a small Edison screw – hence the abbreviation SES. It is often used for lights where space is at a Premium, and for lower-powered bulbs, possibly in fridges, ovens, and other light fittings.
- B22 or Ba22d or just BC: BC standards for Bayonet Cap, and it is the fitting used for standard mains electric light bulbs using a bayonet type cap. The outside diameter is 22mm, excluding the bayonet lugs.
- B15 or Ba15d or SBC: SBC stands for small bayonet cap. Like the small Edison screw, t is used for smaller, lower-powered lamps where space is at a premium. The diameter of the cap or fitting is 15 mm.
Choose an LED Light Bulb in the right colour
The light from various bulbs can look different – some have warm sunshine, others are much colder, much whiter.
The light colour from a bulb, LED, or other source is measured on the Kelvin scale as the “light temperature.” It is known as the light colour temperature.
Technically speaking, the light’s colour temperature is measured in terms of a perfect blackbody radiator’s temperature, which radiates colour light similar to that of the light source.
The colour temperature of incandescent light on the Kelvin scale is around 2700k, and the light of the sunrise or sunset is about 2500 K at midday.
The colour temperature of the light is usually printed inside the box for LED light bulbs. Typically, a warm white around 2700 K is suitable for many homerooms, but this can be chosen personally.
| LIGHT ENVIRONMENT | COLOUR TEMPERATURE °K |
|---|---|
| Candlelight | 1500 |
| Sunrise / sunset | 2500 |
| Traditional incandescent light | 2700 |
| Midday sun | 5000 |
| Overcast sky | 7000 |
| Blue sky | 10000 |
The colour temperature can change the mood for a room – warm white can often be used to relax, while a kitchen or home office may want a whiter light with a higher colour temperature of approximately 5000°C.
LED light bulbs with various colour temperatures are sold – a quick look at an LED light source shows a wide range of colour temperatures and descriptions:
– 2700 k (hot white); 3000 kilos (hot white); 4000 kilos (cool white) and 6000 kilos (hot white) (daylight white). The main requirement is the colour temperature, since descriptions may vary by manufacturer or supplier.
Choose an AMP with the right CRI
As though the colour temperature were insufficient, another commonly used figure, the CRI (colour rendering index), is also used.
This is a measure of the light quality that accurately reflects the articles’ different colours illuminated.
The colour rendering index is a quantitative measure of a light source’s ability to render the colours of different objects accurately, compared with ideal or natural light sources.
The index ranges from 0 to 100 per cent; the higher the CRI, the better the capacity to render colours. In colour rendering, light sources with a CRI of 85-90 are considered good.
Traditional incandescent and halogen bulbs have a perfect CRI score, usually in the high nineties. LED light bulbs and CFLs are not as good, as their CRI values are considered acceptable in the mid-80s.
The CRI system is necessary because all visible frequencies are light. Natural light has a good balance between those frequencies and makes colours the way we are used to. Other light sources may have a different spectral distribution, i.e., a different colour, which means that objects are rendered or seen in a different light.
Dimmable or non-dimmable choice
It was easy to dim bulbs in the days of the incandescent lamps – any of them would dim. CFLs are not dimmable. Do not dim. Some LED light bulbs are dimmable, and others are not. If an LED bulb is dimmed, it must be checked whether it is dimmable. Because LED bulbs operate very differently from other bulb types, the circuitry inside them must be slightly different when designed for dimming.
Most importantly, an LED dimmer is also needed. The way LEDs are dimmed differs from incandescent lamps, so it is essential to use an LED dimmer.
Choose a high-quality LED Light Bulb
It is worth looking for a reliable manufacturer, not just the cheapest, before buying LED light bulbs. The best LED bulbs switch immediately, and others take a second or so after the power is applied. Furthermore, manufacturers will reliably ensure that the LED light bulbs do not reduce output over time – the light output may decrease over time, and the better light outputs will retain much longer. Even LED light bulbs from reputable manufacturers tend to be more reliable, though it can be challenging to quantify.
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