Spotlight problem

[Fotic]

Our house is predominantly lit by spots - 12v ones with the transformers in the ceiling/loft. These are failing at a frustrating rate and it's not the bulbs going, the whole spot seems to have failed! Any thoughts on what it could be? Annoyingly, most of them are in out kitchen which is a single storey thing so I can't access anything from above if you get my drift.

Any advice? Should/could I replace them with LEDs or is there a simpler alternative?

[shtu]

Replace the halogens with -something-, they are incredibly expensive to run, as I've found out lately.

A single 50w halogen used 3 hours a day will be costing in the region of £7 a year to run.

[E36GUY]

Fotic said:

Our house is predominantly lit by spots - 12v ones with the transformers in the ceiling/loft. These are failing at a frustrating rate and it's not the bulbs going, the whole spot seems to have failed! Any thoughts on what it could be? Annoyingly, most of them are in out kitchen which is a single storey thing so I can't access anything from above if you get my drift.

Any advice? Should/could I replace them with LEDs or is there a simpler alternative?

REplacement bulbs in LED won't give you nearly the same output. You need to replace the whole fitting but go with good LED you won't change any more bulbs!

[Fotic]

shtu said:

Replace the halogens with -something-, they are incredibly expensive to run, as I've found out lately.

A single 50w halogen used 3 hours a day will be costing in the region of £7 a year to run.

That's not a huge concern tbh - reckon I can afford a couple.

guy - cheers. Sounds like a ceiling down job do you think?

[shtu]

Fotic said:

Our house is predominantly lit by spots

A couple? Or 20-30? I wasn't concerned at all until I added them up.

[FlossyThePig]

When I bought some LED downlighters I had a chat with the owner of the electrical wholesaler.

Apparently there are two types of 12v Halogen bulbs. The cheap ones let the heat from the bulb rise, which can burn out the fitting. There are other bulbs which project the heat with the light, keeping the fitting cooler.

You can get a replacement lamp holders from places like Toolstation

[E36GUY]

Fotic said:

guy - cheers. Sounds like a ceiling down job do you think?

Shouldn't be. The fittings will likely pull out (be slow and careful lest you damage the hole!) followed by a transformer. If replacing the lights you might find you have to enlarge the holes which isn't the easiest job in the world but is doable.

[Fotic]

Thanks flossy and again Guy.

[NH1]

shtu said:

Replace the halogens with -something-, they are incredibly expensive to run, as I've found out lately.

A single 50w halogen used 3 hours a day will be costing in the region of £7 a year to run.

50W = 20th/kwh, 1kwh=circa 15-20p so to run a 50W lamp for 3 hrs would cost 20/20x3, for a year 3x365=1.09.

So about a £1 a year to run, not £7. Why is there so much scare mongering with halogens.

[NH1]

Its probably too much insulation round the lights thats causing them to fail. Also use a dimmer on them they will last forever, save electric and give a softer light out of an evening.

[hairyben]

FlossyThePig said:

When I bought some LED downlighters I had a chat with the owner of the electrical wholesaler.

Apparently there are two types of 12v Halogen bulbs. The cheap ones let the heat from the bulb rise, which can burn out the fitting. There are other bulbs which project the heat with the light, keeping the fitting cooler.

You can get a replacement lamp holders from places like Toolstation

Man in the shop was talking st. Don't worry sir they all do that. Best is when you're a sparks of 20 years and getting unasked for advice on what you're buying -and being told you're doing it wrong- by some plebian who's spent 5 minutes reading the box and thinks that makes him an expert.

The original dichroic 12v lamps had most of the heat going backwards -hence "cool beam"- as a side-effect of making a reflective backing & glass that would control/filter the light in the best possible way. As fittings were pretty much all open back heat was not an issue.

As most downlights fitted in recent years are stty flawed by design "baked bean can" fire rated highly enclosed types with inherent overheating problems, "heat forward" lamps have been introduced to help mitigate this problem, at the cost of some control & quality of light. The main problem is heat-forward lamps cost more than the cheapest cool-beams, so supermarkets/DIY sheds don't stock 'em, and many so-called sparks are too ignorant to consider the difference. As they're otherwise identical people bung in these cheaper lamps. I spend my life repairing fittings and advising people on what lamps to fit.

This problem was avoided with mains voltage by having GU10's (heat forward) and GZ10's (cool beam) a slightly different shape that won't fit in a GU10 fitting, although the opposite will fit. You can however circumvent the idea and buy cheap chinese cool beam GU10's...

I still recommend and fit open back fittings with separate fabric fire hoods to people wanting halogen downlights.

[Fotic]

I swapped a lamp holder (the little round bit with two wires) for a new one on one of the spots last night and not only did it work but also the transformer and all the wiring came out the hole easily enough too allaying any fears of a new ceiling. Wife's off to get 10 more lamp holders today and then We'll be back in business. It's going to feel very bright.

Thanks again for the responses.

[shtu]

NH1 said:

shtu said:

Replace the halogens with -something-, they are incredibly expensive to run, as I've found out lately.

A single 50w halogen used 3 hours a day will be costing in the region of £7 a year to run.

50W = 20th/kwh, 1kwh=circa 15-20p so to run a 50W lamp for 3 hrs would cost 20/20x3, for a year 3x365=1.09.

So about a £1 a year to run, not £7. Why is there so much scare mongering with halogens.

My number was based on about 13p a kWh

50w = 0.05kW

kW x Hours Used x Unit cost of leccy x Days in year = Cost in £/per annum

0.05 x 3 x 0.15 x 365 = 8.21
0.05 x 3 x 0.20 x 365 = 10.95

Please show me the mistake in my maths, as I'm genuinely not seeing it.

[FlossyThePig]

hairyben said:

FlossyThePig said:

When I bought some LED downlighters I had a chat with the owner of the electrical wholesaler.

Apparently there are two types of 12v Halogen bulbs. The cheap ones let the heat from the bulb rise, which can burn out the fitting. There are other bulbs which project the heat with the light, keeping the fitting cooler.

You can get a replacement lamp holders from places like Toolstation

Man in the shop was talking st. Don't worry sir they all do that. Best is when you're a sparks of 20 years and getting unasked for advice on what you're buying -and being told you're doing it wrong- by some plebian who's spent 5 minutes reading the box and thinks that makes him an expert.

The original dichroic 12v lamps had most of the heat going backwards -hence "cool beam"- as a side-effect of making a reflective backing & glass that would control/filter the light in the best possible way. As fittings were pretty much all open back heat was not an issue.

As most downlights fitted in recent years are stty flawed by design "baked bean can" fire rated highly enclosed types with inherent overheating problems, "heat forward" lamps have been introduced to help mitigate this problem, at the cost of some control & quality of light. The main problem is heat-forward lamps cost more than the cheapest cool-beams, so supermarkets/DIY sheds don't stock 'em, and many so-called sparks are too ignorant to consider the difference. As they're otherwise identical people bung in these cheaper lamps. I spend my life repairing fittings and advising people on what lamps to fit.

This problem was avoided with mains voltage by having GU10's (heat forward) and GZ10's (cool beam) a slightly different shape that won't fit in a GU10 fitting, although the opposite will fit. You can however circumvent the idea and buy cheap chinese cool beam GU10's...

I still recommend and fit open back fittings with separate fabric fire hoods to people wanting halogen downlights.

Good extra detail on my original comment, which I left out because all I wanted to point out was the availability of different bulbs.

The chap I was speaking to was not a "plebian who's spent 5 minutes reading the box and thinks that makes him an expert" and did not comment to the affect "Don't worry sir they all do that" but someone with at least thirty years real experience.

[NH1]

shtu said:

NH1 said:

shtu said:

Replace the halogens with -something-, they are incredibly expensive to run, as I've found out lately.

A single 50w halogen used 3 hours a day will be costing in the region of £7 a year to run.

50W = 20th/kwh, 1kwh=circa 15-20p so to run a 50W lamp for 3 hrs would cost 20/20x3, for a year 3x365=1.09.

So about a £1 a year to run, not £7. Why is there so much scare mongering with halogens.

My number was based on about 13p a kWh

50w = 0.05kW

kW x Hours Used x Unit cost of leccy x Days in year = Cost in £/per annum

0.05 x 3 x 0.15 x 365 = 8.21
0.05 x 3 x 0.20 x 365 = 10.95

Please show me the mistake in my maths, as I'm genuinely not seeing it.

Looks like my mistake, I think I had one too many zeros.

[hairyben]

FlossyThePig said:

Good extra detail on my original comment, which I left out because all I wanted to point out was the availability of different bulbs.

The chap I was speaking to was not a "plebian who's spent 5 minutes reading the box and thinks that makes him an expert" and did not comment to the affect "Don't worry sir they all do that" but someone with at least thirty years real experience.

Fair enough mate I just read your bit about dichroics being "cheaper" and i guess made a similar kind of assumption that I'm complaining about!

(seriously though I've had staff in wholesalers get everything from bolshy to hysterical at what I'm buying because of assumptions they've made about what I'm doing with it... would be like going into marks and sparks and buying some socks, flip flops and cling film and getting condescending spiel on how to dress off the till girl.)