clear or pearl bulb?

pksaraf

everytime i go to buy bulbs, i am split between clear or pearl. I dont really understand the difference between the two, apart from the cosmetics. Does anyone know? Is one better than the other in certain conditions? Is there any other bulb type as well? (amongst the non energy saving ones)

moonrakerz

The difference is mainly cosmetic, a clear one will give a little more (harsher) light, but whether you would notice this .....

WHY are you buying tungsten filament lamps ?????????????

A low energy lamp costs 20% of the running costs of a tungsten filament lamp.

A 20W low energy lamp has a life of 8000 hrs. 8000 X 20 = 160000Watts = 160 kWh (units) @ 10p = £16. Cost of these lamps £1.99, sometimes BOGOF.
Total £17.99.

100W Tungsten lamp has a life of about 1000 hrs. Costs for 8000 hrs are:
8000 X 100 = 800000 Watts = 800kWh @ 10p = £80. Lamps 20p each X 8.
Total £81.60.

The amount of energy wasted by these lamps is staggering ! There are 26 million domestic customers in the UK, if every one of them replaced just ONE tungsten bulb with a low energy lamp the load on the UK's National Grid would be reduced by over 2,000 MegaWatts. Add Industry, offices etc, etc to this ..........

If the government was really serious about saving energy - they would ban the sale of tungsten lamps !

pksaraf

moonrakerz, your post is very useful. I never knew that the difference in costs can be this much! the reason i have not preferred the low energy lamps is because:

1. they produce white lights which doesnt fit in very well with yellow's in case i have other bulbs. this means i have to replace them all with the low energy ones.

2. low energy lamps seem to produce less light compared to the bulbs.

3. i have had bad experience in the past in the sense that they used to last shorter than normal bulbs. your email suggests that they indeed have a longer life, i guess i will try them again.

again, i would be grateful to know experiences of others.

moonrakerz

pksaraf wrote:

low energy lamps seem to produce less light compared to the bulbs.

A 20W low energy lamp produces the same light output as a 100W tungsten lamp... BUT... they do take a few minutes to come up to full brilliance. This slightly "dim" bit is what people tend to notice, not when it has come to full brilliance.

get replacing now - you'll save a fortune !

bunking_off

There's some debate about the use of low energy bulbs, highlighted by Jeff Howell's in the Sunday Telegraph.

His argument is that although a tungsten takes 100W and a low energy 20W to achieve the same light, that excess consumption goes somewhere, and that somewhere is heat. During winter months when you've got the central heating on, the heat generated by the bulb diminishes the heating required by your boiler so by switching to low energy you're merely moving your energy costs. There's something not quite right about that argument that I can't put my finger on (and I have a degree in electronic engineering), but it's an argument.

Not sure I subscribe to the concept of "saving a fortune" with low energy bulbs. 80W saving. Say (probably mad over-estimate) average 4 bulbs on for 6 hours a night in winter, that's 1.92KW/h a day, or £4.80 a month. Better than a kick in the teeth but not what I'd consider a fortune.

Personally, I tend to use the low energy where possible not so much for the energy costs, but because the RCD protectors on my house are so sensitive that when a tungsten bulb goes, it trips the power. Low energies last longer hence not leaving us in the dark so often.

kennyboy66_2

I would suspect the Telegraph is moving on from its previous sceptical line about global warming and is now trying to discredit attempts to save energy.

I'm in no doubt that there is a "warming element effect" of a traditional bulb, but too suggest that people are likely to use their central heating less because of it is simply laughable. Besides electricity is a relativly inefficent method of heating a house compared with gas.

One free way to cut your bills is to read your meter every week and make a note of it. Just doing this will focus the mind enough to switch appliances / lights off and save you money.

moonrakerz

bunking_off wrote:

T
There's something not quite right about that argument that I can't put my finger on (and I have a degree in electronic engineering), but it's an argument.

As you are a graduate you probably haven't noticed that most central heating systems don't have the radiators fitted 7 feet in the air !

:rotfl: :rotfl: :rotfl:

kennyboy66_2

moonrakerz wrote:

As you are a graduate you probably haven't noticed that most central heating systems don't have the radiators fitted 7 feet in the air !

:rotfl: :rotfl: :rotfl:

But he may understand the principle of convection air currents - otherwise we would be standing on chairs to get to the warm air on the ceiling.:)

moonrakerz

kennyboy66 wrote:

But he may understand the principle of convection air currents - otherwise we would be standing on chairs to get to the warm air on the ceiling.:)

True, but it is the cooler air that falls !

Rogerfer

bunking_off wrote:

There's some debate about the use of low energy bulbs, highlighted by Jeff Howell's in the Sunday Telegraph.

His argument is that although a tungsten takes 100W and a low energy 20W to achieve the same light, that excess consumption goes somewhere, and that somewhere is heat. During winter months when you've got the central heating on, the heat generated by the bulb diminishes the heating required by your boiler so by switching to low energy you're merely moving your energy costs. There's something not quite right about that argument that I can't put my finger on (and I have a degree in electronic engineering), but it's an argument.

Not sure I subscribe to the concept of "saving a fortune" with low energy bulbs. 80W saving. Say (probably mad over-estimate) average 4 bulbs on for 6 hours a night in winter, that's 1.92KW/h a day, or £4.80 a month. Better than a kick in the teeth but not what I'd consider a fortune.

Personally, I tend to use the low energy where possible not so much for the energy costs, but because the RCD protectors on my house are so sensitive that when a tungsten bulb goes, it trips the power. Low energies last longer hence not leaving us in the dark so often.

The argument about electric lightbulbs contributing to the heating may be a bit wobbly, depending on what you pay for electricity and heating fuel. It's usually a cost ratio of about 3:1 (electricity:heating fuel).

On that basis there are a negligible number of people who would heat their home from electricity as opposed to some other fuel, (say natural gas) and I wouldn't be one of them unless I had a gun to my head.

My user name is Rogerfer - the last bit I got branded as 'thermal ferret' when I worked as an energy manager for a HVAC maintenance contractor. I subsequently became 'respectable' and 'worked' for a County Council as their Principal Energy & Environment Officer - I leave you to work out what the acronym spells. Anyhow I'm retired now but the collected knowledge lives on

Incidentally, there are a lot more savings using effective heating controls than can be made by insulating the walls-(insulate the hot-water tank) and doubleglazing.

Rogerfer

bunking_off

Rogerfer wrote:

The argument about electric lightbulbs contributing to the heating may be a bit wobbly, depending on what you pay for electricity and heating fuel. It's usually a cost ratio of about 3:1 (electricity:heating fuel).

On that basis there are a negligible number of people who would heat their home from electricity as opposed to some other fuel, (say natural gas) and I wouldn't be one of them unless I had a gun to my head.

Must admit that this was my gut instinct about where the argument fell down.

The bulb being at the top of the room is irrelevant due to convection currents (unless you want to get into real complexities of level of heat loss through walls/ceilings/floors as the temperature in the room equalises). How efficient a lightbulb is versus a radiator is irrelevant, because fundamentally energy in = energy out....if the energy isn't being emitted by light or heat, where is it going?

For what it's worth, I've got a Masters in engineering, but it was many years ago and funnily enough there wasn't a lecture series on the relative heating efficiency of light bulbs and radiators...