Mains Halogen Bulbs

[Stuart]

Can anyone tell me the difference between GU10 and GZ10 Mains Halogen bulbs . The GU10 are described as aluminium . Is it to do with the reflector ?? Stuart

[Andrew Gabriel]

Yes. GZ10 are dichroic lamps which dump a lot of heat back into the fitting. GU10 are aluminium reflector lamps which direct more of the heat out with the light beam.

You can use GU10 lamps in GZ10 fittings, but not the other way round. The lamp bases are slightly different and should prevent GZ10 lamps being used in fittings not designed to handle the extra heat being dumped backwards.

[Al Reynolds]

Even more helpfully, Sainsbury's label them both as dichroic on their price labels!

Cheapest GU10s I've found is Wickes 5 for £15. Anyone seen cheaper? Al

[Stuart]

Screwfix do these

postage of course . Stuart

[Dave Gibson]

Check the nominal lifetime of the bulbs ... the cheapies are generally only rated at 1000hrs, whereas the slightly more expensive ones are 2000 hrs. BTW the screwfix more expensive GU10's are made by Osram and are rated at 2000 hrs.

You pays yer money, yer takes yer choice!

[Andrew Gabriel]

Also bear in mind that the main cost is that of the electricity used, not the bulb. Using a shorter life bulb may give you higher light output and enable use of fewer or lower wattage lamps, which will make a much more significant cost reduction than the difference in bulb prices.

[Dave Gibson]

WTF?

50W is 50W in my book!

1000hrs at 50W costs about £3.00 at 6p per kWh.

2000hrs at 50W costs about £6.00.

Also the GU10's that come *complete* with the fitting I reckon have an average life of 200hrs or less.

Dave

[Dave Plowman]

That's the energy consumed - nothing to do with the light output. Look at fluorescents etc to see the difference between the two. And closer to home, car headlight bulbs vary in light output dramatically for the same power consumption.

Yes, but the light output is also a factor, which you've omitted.

Dunno about that. It will depend on other things.

[The Natural Philosopher]

Got to agree. Bulb cost domiantes in mains halogens.

LV ones its the electricity - over 1000 hours for sure.

[The Natural Philosopher]

Average lightbulb is around 1-2%.efficient. Halogen being at the upper end, and cheapo dim long lifers at the other.

However the eye perceives brightness logarithmically. To be twice as brght probably means 4-10 times the power. That makes efficiencty variations of even 2:1 pretty insignifiocant.

Its pretty irrelevant, as I have indicated.

yeah. Right. Yawn.

>

[Lee Blaver]

snip

The 5 GU10s that came with a £20 fiting we bought from IKEA were all Osram 2000 Hr ones, but I know what you mean ;)

Lee

[Dave Plowman]

I recently changed the bulbs in my car headlights. Same size. The difference in light output was *dramatic*.

I couldn't give a toss about the theory, but the practice means a great deal.

[Capitol]

From what, to what? Regards Capitol

[Dave Gibson]

That's because the old ones are shagged due to the vaporized metal from the filament blackening the inside of the glass envelope. I am assuming they are not halogen (or gas discharge for that matter) which do not suffer such a loss of output with ageing.

Dave

"If you don't know where you are going, any road will take you there"

[Capitol]

Having just had to replace a LV halogen fitting for someone else, my opinion is that the product is a pile of "****". The transformer had failed from overheating(IKEA), was a nightmare to mount and service and had only lasted

3 years. Bearing in mind the cost of the halogen lamps, the short life and the unreliability, long life low energy lamps are a far better product. I recently mounted a mains halogen product, and it suffered from much the same difficulties (and mechanical frailty). There must be a market for attractively styled long life lamps, when do we see the products? Regards Capitol

[Steve Firth]

Err GU10s are 12V, not mains.

[Dave Plowman]

I don't know what sort of car you have, but halogen bulbs have been standard on most for many a year.

Nor were they visibly blackened.

[The Natural Philosopher]

Wattage probably varied then. I got failed on an MOT for having 'wrong bulb' in rear lights. I hadn't - just two different brands.

[The Natural Philosopher]

Well, apart from one out of 25 toroids failing from overheating (buried in isnualtion - even cutout didn't save it) all mey LV enewey and eyere stuff is gound fine.

Just pay a little more and avoid teh sheds.

[Stuart]

all mey LV enewey and eyere ?? translation anyone ??? :-) Stuart