Advice please on: 12 volt Halogen Lights

Hi

I want to install 12 volt halogen lights with individual transformers.
Along with these lights I want to add a 'pull cord dimmer'.

Above the bathroom is the loft.

I have read about 'cool beam' bulbs - and as I understand it, they
direct the heat back up in to the lamp housing/loft area.

I HAVE THREE QUESTIONS

1) Can you recommend a 35 watt or a 50 watt bulb that directs the heat
back into the room?

2) What type of bulb is this known as?

I ask because although I will make sure no insulation is near the lamp
housing I would prefer it not to get so hot and so prevent a possible hazard.

2) Does anyone know the equivalent light output of 35 watt and
50 watt bulbs, compared to say a 60 watt incandescent regular bulb?

Many thanks,

Stephen

Most lamp companies (Sylvania etc) call them "Heat Forward" lamps. They have an aluminimum reflector on the rear.

They are required in most of the modern 'fire rated' fittings as the heat has no where to escape to due to the 'can' of the fitting. Unfortunatley as the fittings will accept both lamps (unlike the GZ and GU 230volt versions), the wrong lamp can be fitted causing damage to the fitting.

The cool beam types are known as "dichroic". They have a glass reflector (the dichroic), which reflects the light but not the heat.

As above but might add something. I guess you are aware that you should use a special dimmer for low voltage lights. Also check your ultimate load on the dimmer. The lasy pull chord dimmer range I used had a measly 200w rating, which would technically let you dimm 4x 50w gu10(alu) lamps (50w 'heat forward' 230v lamps) although I would not max a dimmers stated load as good practice. The 12v versions of the lamps you asked for are MR16(alu).
Zeus.

zappastix said:

1) Can you recommend a 35 watt or a 50 watt bulb that directs the heat
back into the room?
2) What type of bulb is this known as?

Click to expand...

Any with an aluminium reflector, described as aluminium / PAR / coolfit.

Downlighters should NEVER be fitted with lamps described as dichroic or coolbeam.

zappastix said:

I ask because although I will make sure no insulation is near the lamp housing

Click to expand...

This project is doomed, since installing these lights is notifiable work, the fee for which will be many times greater than the cost of the lights.
Regarding building regulations, big holes in the insulation isn't allowed, a majority of downlighter fittings won't comply unless additional airtight sealed covers are fitted above them, and as for energy efficiency, no halogen downlighters will comply.
Further, halogen lamps and dimmers should not be used together, as this will dramatically shorten the lamp life, and good luck finding a pull cord dimmer which can operate enough of these downlighters to actually illuminate the room, and not be incompatible with the transformers causing loud buzzing or destroying the dimmer, transformers or both.

I will pick on this question as it is the easiest to answer.

zappastix said:

2) Does anyone know the equivalent light output of 35 watt and
50 watt bulbs, compared to say a 60 watt incandescent regular bulb?

Click to expand...

Downlights are called downlights because they light, well, down.

And they don't even light down all that well.

They certainly do not send out any light sideways - that is why they are called DOWNlights.

A GLS incandescent BULB is round and emits light out probably 320º
A downlight emits light at around 40º

A 60watt incandescent lamp will illuminate the average bathroom (lets say 3metres x 3 metres.)

To provide a similar light intensity using GU10 or MR16 lamps you may need 4-6 lamps each of 50watts. So that's 300watts or 5 times as much energy as a regular incandescent lamp - and you'll probbaly need an extra light over the mirror so you can see to scrape off your stubble.

Does that answer your question?
Are you still going to make swiss cheese out of your bathroom ceiling, with all of the steamy moisture being drawn into the roof space where it will rot your roof timbers?
Will you look at your bathroom ceiling in 3 years time (when everyone will say "oh downlights, that's soooooo last century") and try and find a plasterer who will make it look like it used to?
Or will you now think constructively about effective, alternate and energy efficient ways of lighting your bathroom?

Oh yes, and PS. Do not forget that fitting downlights in a bathroom is notifiable work which will cost you ££££££££ in building regulations paperwork (if you do it yourself) or slightly less £££££££££ if you use a registered electrician.