Q: What sort of bulb should I buy? 
A: Firstly ensure you know the type of light fitting you require, for example bayonet or screw cap. Efficient Lighting stock a range of different fittings, including the small bayonet and screw caps, and have a light bulb calculator. Secondly consider the use of your particular light and size the bulb appropriately. Small bedside lights will require less power (Watts) than a bulb to light an entire room. See our website for Oxfordshire stockists- Eco-St (Yarnton and Chinnor) have the largest in-store range that we can find, plus a light.-bulb finder.
Q: Do Compact Flourescent Lights (CFLs) flicker when you turn them on?
A: There is no 'flicker' associated with the newer range of CFL bulbs.
Q: Do CFLs take time to "warm up"?
A: The start up time is different for each model. The reflector and spiral bulbs have instant light and require no 'start up' time at all. The other bulbs available are still significantly better than most bulbs on the market in terms of a very short start up time. Again remember that the quality of bulbs has improved vastly over the last couple of years.
Q: What light bulb energy savings can be expected when replacing incandescent bulbs with compact fluorescent light bulbs?
A: Compact fluorescent light bulbs use about 70% less energy than a standard incandescent light bulb and last up to 10 times longer. There's a handy light bulb calculator on Eco-St's website - where you can enter the bulb you have, and it will show a suggested replacement, plus the energy savings - and you can do it for the entire house.
Q. Which is the best Dimmable CFL bulb?
There are a number of dimmable bulbs on the market now . Some are fully dimmable, others dimmable in steps. See the Lighting Magazine's article for a comparison of the dimmable bulbs - well worth a read.
To get the most out of your dimmable bulbs, they need to be compatible with your dimmer switches. The lowest rated standard dimmer switches are 250W (i.e. 250W maximum on the circuit). The minimum these units can work with is 60W. Hence a minimum of 3 x 20W bulbs would be necessary. Dimmer switches for CFLS can be obtained here from 1 Stop electrics .
Two experiences of dimmer lights:
1. "We've got 4 of the Varilight CFLs at home, 2 per dimmer circuit, and they seem to be working - a bit of buzzing and quite blue at low-energy levels, but not as incompatible with our pre-existing dimmer switches as I feared. So far ..."
2. "My experience with the Varilights seems a bit better than this. We have two (one on each circuit) and they seem to work fine wherever I have tried them. Currently in use in our family room with no real problems - slight buzzing noise from the dimmer if you put your ear to it, but not audible in the room. Also the colour tone seems fine (though maybe the lampshade helps in this respect).
I also have one Megaman in use (and more waiting to be fitted). These seem more temperamental, but work OK with Varilight dimmers - again 1 bulb per circuit. The advantage of the Megaman bulbs is that they are available in a wider range of bulb types and fittings (e.g. candle bulbs with small bayonet fittings, which is what I need in the living room)."
Q. Isn't there a high mercury content in CFLs?
A:. Life-cycle mercury emissions from CFL lighting are similar to those from filament / incandescent lighting.
With the current UK fuel mix, approximately 15mg of mercury is emitted during the lifetime of an ordinary bulb through energy generation (coal fired power stations), compared with approx 3mg during the lifetime of a CFL, so during the lifetime a CFL accounts for approx 6mg of mercury (3mg in the bulb, 3mg from the electricity), compared with 15mg from an incandescent bulb (from electricity generation.
There is approximately 3mg of mercury in a CFL bulb, whilst incandescent bulbs don't contain any mercury. Mercury is emitted from coal fired power stations however, so the more energy a bulb needs, the more mercury is emitted. See the examples below for a comparison of life cycle mercury emitted, and an additional article here (although the article assumes that the electricity is from a coal power plant).
You should make sure the bulbs you buy are both ROHS and WEE Compliant, this means there they are compliant with strict EU Legislation. You should ask your Local Authority to ensure that recycling facilities are available for CFL bulbs.
Where mercury is emitted during the lifecyle of a bulb:
- Coal-fired electricity generation results in approx 0.025mg Mercury (Hg)/kWh
- In the UK, coal accounts for about a third of the electricity mix
- Therefore, 1kWh in UK = 0.008mg Hg.
- CFLs contain approx 3mg Hg per bulb
- CFLs consume around a quarter of the energy of filament bulbs.
- CFLs may last around 8,000 hours
Examples:
A 60W equivalent CFL will use 15W. Over 8,000 hours the bulb will use 120 kWh and 1mg Hg. Total Hg emissions are 3+1 = 4mg. A 60W standard bulb will use 480kWh and 4mg Hg. Total Hg emissions are the same.
A 100W equivalent CFL will use 23W. Over 8,000 hours the bulb will use 184 kWh and 1.5mg Hg. Total Hg emissions are 3+1.5 = 4.5mg. A 100W standard bulb will use 736kWh and 6mg Hg. Total Hg emissions are lower for the CFL.
A 40W equivalent CFL will use 11W. Over 8,000 hours the bulb will use 88 kWh and 0.7mg Hg. Total Hg emissions are 3+0.7 = 3.7mg. A 40W standard bulb will use 320kWh and 2.6mg Hg. Total Hg emissions are higher for the CFL.
LED FAQ's
Q: What is an LED? 
A: A light-emitting diode (LED) is a semiconductor device that emits narrow-spectrum light when electrically charged. An LED is a small bulb previously used in millions of physics experiments at school to demonstrate electrical current, use of switches etc. LED's are being improved all the time to progress from experimental devices into the future of lighting technology.
Q: How efficient are LED bulbs compared to incandescent bulbs?
A: Most LED light bulbs are four times as efficient as incandescent bulbs. In other words, they use only 25% as much electricity to produce the same amount of light. The newest generation of leds are eight to ten times as efficient as incandescent bulbs.
Q: How long do LEDs last?
A: LEDs can operate for 30,000 hours or more. One LED bulb can outlast 30 incandescent bulbs, or 6 compact fluorescents. Operating 12 hours per day, LED bulbs can last 7 years or more. See the article here for more examples of where they've been fitted.
Q. What should I look for in a LED?
A: Ensure that the bulb has a suitable heat sink - ‘fins' radiate the heat away effectively, but cheaper LED bulbs might not have these - which may mean a shorter lifetime for the bulb.
Q.Can I replace any halogen light with an LED?
A. It depends what system you're using - some LEDs need transformers, but the GU10 variety can go straight into a halogen 230w socket.
Q. How many different sorts of LED are there?
A. How long is a piece opf string?...check Efficient Light's and Eco-St's ranges.
Still unanswered questions? Check the links on the right for more info.
