October 21 2020 0Comment


LED lights have a longer lifespan when compared with traditional light sources like halogens, incandescent, compact and tubular fluorescent lamps, high intensity/high pressure discharge lamps. The average LED lasts 40,000 operating hours to 100,000 operating hours or more. LEDs are 2-4 times as long as most fluorescent, metal halide, and even sodium vapor lights. It is more than 40 times as long as the average incandescent bulb.


A color rendering is a quantitative measure of the ability of a light source to reveal the colors of various objects faithfully in comparison with an ideal or natural light source. High CRI is generally a desirable characteristics, measured on a scale where a higher number represents higher ability, with 100 being the highest. Generally, a CRI of 80 or above is considered good, while a CRI of 90 or better is thought of as excellent.

Different type of light bulbs have different color rendering abilities. High pressure sodium (HPS) and mercury vapour lamps (MVL) are at the bottom with 24 and 49 respectively. Depending on coating, fluorescent (FLU) has a CRI range of 50 to 85. LEDs however can boast of CRIs into the high 90s. See the chart below with showing various CRIs of various light sources.


The statistics to look for when comparing the energy efficiency of different lighting sources is luminous efficacy, simply called lumen. Lumens/Watt indicates the amount of visible light the bulb emits for a given amount of energy required to generate it. It is a simple measure of energy efficiency where the higher the value the more efficient the light.

LED lighting has had improved luminous efficacy from around 25lm/W to over 160lm/W depending on the color quality and drive conditions. The efficacy of LED lighting products compared better to conventional lighting products. The table below shows luminous efficacy comparison between LEDs and other lights.


Most light source emit lights around the source at 360 degree but LED have directional emissions radiating light at 180 degrees. The advantage is that, with 360 degree emissions, light could be emitted in some unwanted places, examples into the ceiling of homes. This can generally result in losses and drives up the overall cost of the light. With the directional effects of LEDs, light is emitted in the direction of revelance. This improves the overall energy efficiency of LED lights.

The high efficiency and directional nature of LEDs makes them ideal for many industrial uses. LEDs are also commonly used in street lighting, parking garage lighting, walkway and other outdoor area lighting, refrigerated case lighting, Down recess lights are used in residential kitchens, hallways, and bathrooms and in a number of office and commercial settings. Below is some LED applications in kitchen and supermarkets.


The law of conservation of energy states that, energy can neither be created nor destroyed, rather can be transformed from one state to another. In the case of light bulbs, the electrical energy from the source is transformed to light and heat (thermal) energy. The number one hazard when it comes to lighting is the emissions of heat.

For incandescent bulbs, only about 10% of the energy used is converted to light whilst the rest lost as heat. For fluorescent bulbs, about 85% of the energy used is converted into light. LED on the other hand, transforms 90% of the energy into useful lights. This makes LED lights more electricity efficient than the other light sources, with almost no heat emissions.


With LED technology, it really is possible to have it all:  longer lifespan lower energy costs, good color rendering index, low heat emissions and improved safety. This our next article we will continue to look at other benefits to LED lights over traditional lamps.

At Rhema Engineering, we have all the various types of LED lights that you will need for your office, lamps, factories, gas stations, schools, hospitals etc. We will be happy to meet you and help you assess your lighting and energy management needs

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