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The case for energy efficient lamps1


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The information set out below is intended as a very general introduction to energy efficient lamps
for non-technical people. It is intended to give sufficient information to discuss your plans with
your electrician.

There has been a lot of information in the press lately about using energy efficient lamps because of
their lower environmental impact. You may be familiar with them as “giveaways” by some
electricity companies or the types which are now being used a lot in such items as table lamps. Be
aware that these types of lamps now come in many shapes, sizes, wattages and colours i.e. warm
white, cool white etc. The range of lamps and the fittings they are now being used in is constantly
growing so you may not be familiar with just what is now available.

So just what are they?
They are often sold as direct replacements for conventional bulbs which cost much less to run. This
is because they give a similar light output level to a conventional bulb but achieve this with a lower
wattage. In essence they are fluorescent tubes controlled by modern electronics all wrapped up in a
small package. The modern electronics ensures that they are flicker free and run considerably more
efficiently than conventional bulbs or old style fluorescent tubes. However it is important to note
that the colour of the light output is not the same as a conventional or tungsten down lighter bulbs
because the technology is different. They do not have that bright sparkle look of tungsten down
lighters but are bright none the less. The lamps do come in a variety of colours. Warm white most
closely mimics the colour of conventional bulbs so is good for table lamps etc. but for kitchen
lighting a daylight colour may be more appropriate.

Where can they be used?
They can be used almost anywhere but due to the fact that they take a little while to come to full
brightness (a few seconds to a couple of minutes or so depending on the type), it is not advisable to
use them where lights are only switched on for short periods of time, such as an under stair
cupboards or outside lights which are controlled by a PIR sensor.
Energy efficient lamps are best suited to where lights are left on for reasonably long periods of time
or where they are forgotten about and left on, such as hall ways or kitchens.
Energy efficient lamps also run cooler than conventional bulbs, particularly those in down lighters
or similar which get extremely hot. This makes them a perfect replacement for fittings which suffer
from heat damage, such as down lighters or for use in fire risk areas.

How much do they cost to run?
This of course depends on how many lamps you have and how much you are paying for your
electricity as well as many other variable factors.
However, to get some idea, it may be simpler to look at it in terms of wattages which will give a
feel for the savings to be made. E.g. a 60W conventional bulb can be replaced by an 11W energy
efficient lamp, which is a power saving of 49Watts. That’s 49 Watts of electricity that you are now
not paying for! Multiply this wattage by the number of lights you are thinking of changing and you
can work out the amount of money you could save.
Below is an example of a cost saving in a kitchen with 10 down lighters at 50W each. These are
being run for 3 hours a day and are being replaced by 11W energy efficient lamps. The cost of
electricity and the running time remains the same in both cases.
Existing costs with conventional lighting
Total load 500W for 3 hours a day costs £51.61 per year            £258.03 per 5 Years

New costs with energy efficient lighting
Total load 110W for 3 hours a day costs     £11.35 per year        £56.77 per 5 Years

Savings                                     £ 40.26 per year       £201.26 per 5 years
March 2010 prices

How long do the lamps last?
This varies with each type of lamp and must be checked. However, normally they last between
10,000 – 17,000 hours, which is considerably more than the 2,000 hours of a conventional bulb. To
put this into perspective, an energy efficient lamp with an average lifetime of 13,500 hours running
for 3 hours a day (as per the example above) would theoretically last for 12.3 years. What this
means is that a conventional bulb would need to be purchased and changed on average 6 - 7 times
to equal the one energy efficient lamp. This long lifetime makes energy efficient lamps particularly
useful for places where changing the bulb is difficult.

How much do the lamps cost?
Of course prices are changing all the time and as these types of lamps become more popular I hope
that the costs will come down. There are so many different types of lamps that the issue of cost
needs to be looked at on a case by case basis. However, generally speaking they are 2 – 3 times or
more the cost of a conventional lamp. Whilst this seems a big draw back, remember that you will
need to replace the conventional bulb on average 6 - 7 times to obtain the same lifetime as an
energy efficient lamp. This in fact makes energy efficient lamps generally cheaper over their
lifetime. Plus of course you will have the savings in the electricity bill.

In summery
Set out below are the basic advantages and disadvantages of these types of lamps.

Advantages of using energy efficient lamps
  1. Cost less to run so saves you money on running costs.
  2. Long lamp life so you do not need to keep changing lamps.
  3. Run cooler than many conventional bulbs so they present less of a fire risk and cause less
     damage to fittings. This is particularly relevant to down lighters.

Disadvantages of using energy efficient lamps
   1. Cost more initially but generally not over the lamp life.
   2. Lamp colour is not always the same as conventional bulbs.
   3. They have a warm up time.
   4. They do not have that bright sparkle look of some down lighters.

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