In the face of frequent power cuts and emerging energy crisis, there is an urgent need to focus on energy conservation and management.
Energy efficient light bulbs are light sources that use energy successfully, efficiently and sparingly. We can build a friendly environment and good health by using energy efficiency light bulbs.
Even though you may not be aware of it, lighting in households consumes a substantial amount of energy of your home energy budget. So we should start with energy conservation when choosing light bulbs for our home, shop or office. For this, it is important to be aware of the lighting and energy efficiency of the bulbs.
Light sources come in a variety of shapes and sizes, light outputs (brightness) and light appearance (colour temperatures). Early light bulbs were incandescent light bulbs. Later, CFL (Compact Fluorescent Light) and LED (Light Emitting Diode) were developed as a result of continuous research by scientists. They are much more efficient than incandescent bulbs.
What are light bulb attributes?
Light bulb attributes are the features of a bulb that allow you to narrow your selection and ensure that you choose the one that is right for you. Usually, information on these attributes is found on the light bulb packaging. They include:
* Shape and sizes
Often determined by the light fixture the bulb is for (Eg: A desk lamp with a shade, a pendant, and a recessed down light or a track)
* Brightness (light output)
The amount of light you want. Brightness is measured in lumens (lm); the higher the lumens, the brighter the light.
* Light appearance (correlated color temperature)
Describes the mood created by the lighting (i.e. how warm or cool the space feels). The temperature of the light source is measured in degrees Kelvin (°K); the lower the number, the wormer the light source. For example, an incandescent light bulb would typically have a correlated colour temperature of about 3000°K. Colour temperature generally ranges from 2700 – 3300 °K (warm – produces a yellowish light) to 3300 – 5300 (cool – produces a bluish color) – and 6500°K is daylight.
* Efficiency
The amount of power required to produce the light output, this is a key metric. Make sure to compare the light output (Lumens) with the energy used (Watts) to provide the light output. Watts indicate the amount of power used by the bulb. Lumens indicate the amount of light provided by the bulb. Comparisons based on wattage can be misleading because different bulbs can use very different amount of energy (watts) to produce the same amount of light (lumens). Measuring the performance of a bulb in lumens allows direct comparisons of light quantity.
The easiest way to choose an energy efficient bulb is to look for the energy star symbol or efficacy value.
* Rated life
How long the bulb will last. Energy efficient bulbs last a lot longer than traditional incandescent bulbs.
* Dimmability
This determines if the light level can be adjusted. Dimmers can save electricity when they are used to lower light levels. Note that the dimmer switch must be compatible with the type of bulb.
Let’s take a look at the energy efficiency of some of the most commonly used light bulbs and the labels to consider when purchasing them.
Halogen light bulbs
Halogen light bulbs use up to at least 28 percent less energy, produce more light for the same amount of energy and last up to three times longer than traditional incandescent bulbs. They are available in a wide range of shapes and colors and can be used anywhere a traditional incandescent bulb is used and for the same purpose.
CFL bulbs
Compact Fluorescent Light (CFL) bulbs have improved tremendously since they were first introduced in the 1980s. They start almost instantly, do not buzz or flicker, contain less mercury, and many are dimmable, all recent improvements. CFLs produce the same light output and warm colors as incandescent bulbs and are very energy efficient.
Energy star qualified CFL use up to 75 percent less energy and last up to 10 times longer than traditional incandescent light bulbs. The Sri Lanka Standards Institution and Sri Lanka Sustainable Energy Authority have introduced a special label to make it easier for consumers to identify energy efficient CFL bulbs.
If the condition of any CFL bulb model is compliant with SLS 1225:2016 before it is released to the market, those bulbs will be given an energy efficiency label. CFL lamp shall be labelled with the approved star rating for the model of the lamp. The format of the label shall be as given in figure. You can get more information about the bulb, before you buy it. It is important to be aware of this label in order to contribute to energy conservation.
a - Number of stars appearing on the curved band depends on the energy rating determined as the standard. More stars mean higher energy efficient.
b - Number of stars permitted for the model.
c - Brand name and model number of the lamp shall be printed in the space provided.
d - Average measured power in Watts.
LED bulbs
Light Emitting Diode (LED) light bulbs are quickly evolving and are now available for most residential applications. LED bulbs offer similar light quality to traditional incandescent bulbs, last 25 times longer and use even less energy than CFLs. They start quickly, are dimmable, can operate in all weather conditions and are very durable. The design of LED products is crucial to good performance. Choose LED bulbs that are Minimum Energy Performance (MEP) qualified for the highest quality and energy savings.
We can see the Minimum Energy Performance label (MEP label) on the packaging of LED bulb models that meet the requirements of SLS 1530:2016. This minimum energy performance standard for integral type LED lamps for general lighting services has been published for the promotion of the use of efficient lamps for saving electrical energy. The format of the MEP label is given in figure 2.
a – Efficacy of the lamp
LED efficacy is calculated by lumens divided by watts. This will tell you how well and LED fixture or lamp will produce visible light. There are several different LED tubes on the market. When you compare LED efficacy, it will help to identify what bulb you should buy. Let’s consider an example, one bulb is 15 watts delivering 2100 lumens and another bulb is 18 Watts delivering 1800 lumens. First bulb efficacy is 140 lumens per watt. The second bulb efficacy is 100 lumens per Watt. A higher efficacy equals more energy savings over the long term of a project by using less energy to deliver more lumens.
b – Average measured power in watt.
c – Monthly energy consumption of the lamp considering 4 hours per day operation.
d –Brand name, model number and the light output of the lamp shall be printed in the space provided.
It is a matter of urgency to remove incandescent bulbs from your home, office shop and replace it with LEDs or CFLs. Experience the change in the monthly electricity bill through these changes. It is going to be cheaper for you. If we personally get used to using energy efficient light bulbs individually, there will be huge energy savings as a country. Therefore, the tendency to use more energy efficient light bulbs with a longer lifespan is a key foundation for facing the energy crisis of the future.
The writer is a member of the Sri Lanka Energy Managers Association
