What's wrong with low energy bulb ratings?

andrewmoorcroft

i've done some tests with traditional light bulbs and the low energy saving ones which are labelled with the actual low wattage value and the equivalent light value compared with traditional bulb. On every occasion even when i've left them on for a few minutes, the low energy ones are never as bright as claimed, so as i replace my old bulbs use a higher output one than the suposing equivalent. for example when i replace a 60W bulb i use a 100W low watt equivalent to get a similar brightness of a 60W bulb. Can't remember the exact figures but i think it means buying a 15W instead of a 11W maybe. Of course this is still cheaper to run than a traditional 60W but whats gone wrong with the equivalent labelling or have i missed the plot? does anyone else have this problem and can they explain why?

Jet

I'm glad it's not just me that's noticed this.

Most of my fittings can't take the low energy bulbs but the few that can, are definetly dimmer than the equivalent "normal" 60w bulb even though I use the energy saving equivalent.

Poppycat

I know some of the old bulbs use to take a while to warm up, this really isn't much of a problem with the new bulbs.

Its donkeys years since I used conventionality bulbs now so I cant compare.

Sorry cant help much more

illuminate

How have you measured their output ?

There are differences between the 2 sources.

A standard GLS lamp will actually increase in output with age, a compact fluorescent is the reverse.

Compacts are also incredibly susceptible (sic) to temperature.

There are also colour issues which effect "perceived" brightness.

Other factors revolve around the manufacturer. This sector, particularly at the retail end, has been dominated with cheap (Chinese) imports. Rather that photometrically test their products, they are happy just to quote branded lamp performances.

The right brand WILL do exactly what it says on the box.

roswell

have you checked the lux readings? a old style buld is at its brightest just before it pops :-) compacts go dinner with age and use, Also you could try using daylight bulbs if you want more brightness but expect your eyes to hurt if your exposed to them for long periods.

andrewmoorcroft

illuminate wrote:

How have you measured their output ?

Compacts are also incredibly susceptible (sic) to temperature.

Other factors revolve around the manufacturer. This sector, particularly at the retail end, has been dominated with cheap (Chinese) imports. Rather that photometrically test their products, they are happy just to quote branded lamp performances.

The right brand WILL do exactly what it says on the box.

Strangely enough i have no objective measurement of the luminous intensity of my bulbs!
My back to back tests are merely subjective.
For example; i can read in bed with a 60W traditional bulb but can't with a low energy 60W equivalent. My wife walks in the room after i've secretly changed the bulbs and says 'why is it so dark in here'.
I have tried a few makes of new low energy bulbs including osram, philips, and GET and they are all subjectively duller.
Like most rooms mine is 20degC.
Whatever the method of deciding equivalent brightness, i think that the general public expect to see as well in a room lit with a 60W low energy equivalent as they do with a traditional 60W. If this is not the intention of the equivalence values then it is misleading to the majority of the non expert public who hasn't even heared of the candela!

cat70_3

I agree, the latest ones do (subjectively at least) seem less bright than conventional bulbs. But they're not half as bad as they used to be. They're brighter, take less time to "warm up", and the savings are impressive.

We have 2 types in our house - Philips Softone, which have the advantage of looking like a normal lightbulb, and Osram 12-year, which are brighter and last longer but look like compact flourescent. Both are 20W bulbs sold as 100W equivalents and I think that they're both good enough to use.

The best thing about both of these bulbs is that you can buy them very cheaply because they're subsidised - much, much cheaper than High Street prices! - I got them online for £2.65 plus vat (great when you consider that the Osram lasts 12 years and the Philips 6 years).

See http://www.homesandbargains.co.uk/view_listing.php?id=55

illuminate

Perceived brightness is what we are talking about her, and its all about the quality of light from the 2 sources..... not the amount.

Tungsten sources such as GLS lamp render all colours perfectly.

Fluorescent sources, such as the CFL lamps you are talking about, have certain wavelengths of light missing from the spectrum that they emit. Therefore they render many colours particularly poorly.

The actual amount or "lumens" that 2 lamps emit may be exactly the same, but because 1 fails to make a particular colour jump out at you it will be perceived as being of lower in output, when its just that the colours are less vivid.

Now its possible to measure the output of a lamp - lumens.

And its also possible to state its ability to render colour - Ra. (The latter is a relative figure.... expressed as a percentage.... where 100 percent is a tungsten source.

However its not possible to combine the 2 as there are many other determining factors. Not least of which is the eyesight of us poor humans.

scorour

I know these will probably be imports as mentioned above in thread, but next Thursday, Aldi have CFL bulbs on their special for 99p. I know these may not be the as good as brands, but they will do for a couple of locations in the house for me where I am not too fussed about matching output etc (loft, cupboards, kids play room)

illuminate

scorour wrote:

I know these will probably be imports as mentioned above in thread, but next Thursday, Aldi have CFL bulbs on their special for 99p. I know these may not be the as good as brands, but they will do for a couple of locations in the house for me where I am not too fussed about matching output etc (loft, cupboards, kids play room)

At 99p you probably can't go wrong !

scorour

Illuminate,
It is obvious that you really know what you are on about when it comes to lights etc :T , so I wondered if you had any idea for a problem I have? (Sorry if it is off topic)

When we bought our house, the bathroom contained/contains 6 halogen lights scatterered around the ceiling. I do not like these halogen as sometimes it like a disco, lights on and off randomly...plus these need replacing a lot! I would like to change them, but wondered if there was something else (better) that might fit into the same holes already in the ceiling so I do not have to refill all six holes? (I know a sparky who would do any wiring/fixture replacement).

Not sure if any such thing exists, just wanted to check before fillling in the 6 holes and fitting another light?

Any info appreciated.

Cheers,
Steve