1 LED Lighting and Sustainability.
LED lighting technology contributes to environmental sustainability through energy efficiency and hazardous waste reduction.
1.1 Energy Efficiency
Modern LEDs have a luminous efficacy of approximately 170lm/W in comparison to 10-15lm/W for incandescent lamps and 60-80lm/W for a fluorescent tubes. This results in more light per watt of input power and hence fewer required light fittings for a given area. The efficient lumen per watt ratio of LEDs means a significantly reduced electrical lighting load for a building can be achieved resulting in lower carbon footprint and greenhouse gas (GHG) emissions. The ease at which LED fittings can be further controlled, i.e. via presence detectors or photocells and to which they can be dimmed enable them to offer further energy saving features and help contribute to a sustainable future.
LED light emission is directional and can emit light for 180 degrees, compared to fluorescent and discharge lamps, which emit all 360 degrees around the lamp, This directional feature is typically an advantage because light is usually desired over a target area, and so LEDS emit less glare, overspill and uplight / sky glow pollution, features that further contribute to energy efficiency by reducing waste light. You can read more about the impact of directional lighting by learning about a measurement called “useful lumens” or “system efficiency.”
LEDs have virtually zero maintenance costs and the frequency with which lamps have to be changed out is by far the best on the market. Fluorescent bulbs require regular re-lamping and ballast replacement in addition to the labour cost to monitor and replace ageing or expired components.
1.2 Waste Reduction
1.2.1 Hazardous Waste
Fluorescent and other discharge lighting types uses environmentally hazardous chemicals, such as Mercury, which can be leaked into the environment if the lamps break. LED luminaries have no such hazardous components and present no danger to the environment if broken.
Furthermore, LEDs have a much longer operating life, up to six times that of fluorescents tubes, and so each LED fitting would negate the production and disposal of six equivalent fluorescent fittings, providing less environmental impact over its life. LED Lamps can also be recycled.
Fluorescent lights primarily produce UV radiation. They generate visible light because the lamp is coated with a layer of phosphor which glows when it comes into contact with UV radiation. Although most UV radiation stays within the lamp, some does escape into the environment which can hazardous to skin and the eyes over time, while also biologically harmful to cell reproduction.
Finally, lower power results in lower current, and lower current means less copper required in the cables supplying the LED circuits, relieving demand on the earths copper resources.
LED Lamps last longer than any light source commercially available on the market. Lifespans are variable but typical values range from 25,000 hours to 200,000 hours or more before a lamp or fixture requires replacement. Fluorescent lights have good lifespan relative to other conventional lamps but not compared to LED. Typical fluorescent lifespan values range from 7,000 hours to 15,000 hours before a lamp requires replacement. Note: sometimes fluorescent lights need to be changed out before the end of their useful life to pre-empt serious degradation effects like flicker or changing light color (turning pink).
1.2.3 Lifetime Cost
LED lighting has relatively high initial costs and low lifetime costs. The technology pays the investor back over time (the payback period). The major payback comes primarily from reduced maintenance costs over time (dependent on labour costs) and secondarily from energy efficiency improvements (dependent on electricity costs). Fluorescent lights are relatively cheap to purchase but relatively expensive to maintain. Fluorescent bulbs will likely need to be purchased several times and the associated labour costs will need to be paid in order to attain the equivalent lifespan of a single LED light.
2 LEDs Light and Heat (IR) / Ultra Violet (UV) Emissions
2.1.1 Infra Red Radiation (Heat)
LED luminaires convert more than 50% of their total input power into visible light, a significant improvement on incandescent and fluorescent luminaries which only convert approximately 10% and 20% respectively. The resulting (wasted) energy is emitted in mainly infra-red (Heat) and Ultra-Violet (UV) spectrums. Heat emission from incandescent and fluorescents lamps add to the overall heat load in the building increasing the mechanical cooling requirement and in turn the electrical building load, GHG emissions and carbon footprint. Efficient LED lamps means significantly less heat emission per lamp and less waste heat offloaded onto the building A/C cooling system to deal with.
2.1.2 Ultra-Violet Radiation (UV)
LEDs produce a very narrow spectrum of visible light without the losses to irrelevant radiation types (IR or UV) associated with conventional lighting, meaning that most of the energy consumed by the light source is converted directly to visible light. Fluorescent lights actually produce primarily UV radiation. They generate visible light because the lamp is coated with a layer of phosphor which glows when it comes into contact with UV radiation.