Little Gransden Energy Group (LGEG) Nov 2012
Solar pv panels: The “Which?” magazine carried out an evaluation on the cost effectiveness of installing solar pv panels, now that the Feed in Tariff (FiT) has been reduced so much. They concluded that it is still financially beneficial, provided that the income from the FiT is paid back in to a Cash ISA to improve the financial return.
Electricity supplies: “Which?” magazine also reminded us that the cost of electricity has doubled between 2004 and 2012, and we have just heard of further increases of around 6% later this year. The only ways to contain the cost of electricity is to avoid wasting power, and installing more efficient lights and appliances.
Energy saving lights: The European governments are forcing us to change from the inefficient tungsten bulbs (which give out more heat than light), by severely restricting the sale of tungsten bulbs. Halogen lights are only 20% more efficient than tungsten bulbs. Compact fluorescent lamps (CFL) are more efficient, but disliked by many people, because of the flickering and dim start up. The light bulbs of the future are undoubtedly LEDs, but these are quite expensive to buy. However, LEDs use about 12% of the electricity compared to CFLs, last about 5 times longer, and instantly achieve full brightness. Compared to tungsten bulbs, LEDs use about 2-3% of electricity, should last around 25 years. Unfortunately, at present LEDs are only bright enough to replace tungsten bulbs up to 60 watts.
Lumens is the new measure of light output, and is applied to tungsten, CFL, and LED bulbs. Wattage is the amount of electricity used by a bulb.
A 40 watt tungsten bulb may emit 300 to 500 lumens, equivalent to 7 to 11 watts for a CFL.
A 60 watt tungsten bulb may emit 500 to 800 lumens, equivalent to 8 to 15 watts for a CFL.
A 100 watt tungsten bulb may emit 900 to 1300 lumens, equivalent to 15 to 20 watts for a CFL.
Not all bulbs are equal: “Which?” magazine found that some CFLs started quicker, and brighter, than others – GE 8 watt energy saving spiral bulbs were the quickest to start (470 lumens, equivalent to 40 watt tungsten). Megaman Modo 8 watt stick bulb was nearly as quick as the GE bulb (420 lumens, equivalent to 40 watt tungsten). Ikea’s Sparsam 15 watt was also rated highly for speed of illumination (820 lumens, equivalent to 100 watt tungsten).
“Best buy” LEDs include Philips MyVision 5W (250 lumens), Osram Parathorn Pro Classic A60 (650 lumens), Sylvania Toledo GLS A60 (250 lumens).
I have successfully replaced a B&Q 11 watt CFL with a Philips Econic 7W warm white LED (350 lumens), which gave similar light output and immediate start up.
Tungsten bulbs give a warm white colour light, which is equivalent to 2700K colour temperature of light. For comparison, candle light is 1850K, halogen bulbs produce light at 3500K, noon daylight is 5000K, blue sky, daylight lamps, and SAD light, is at 6500K to 7000K.
Trevor Brown on telephone 677285, email: firstname.lastname@example.org.