Which bulbs for G5.3 12V DIMMABLE halogen spot, not dichroic

[EmyEmy]

Hi there,

We've bought 5 halogen spots for our bathroom, label on side reads G5.3 12VOLT 50W MAX. I've been searching online for the bulbs for these but all seem to say they are not DIMMABLE, and my electrician has already installed my dimmer!

They also say that they are dichroic, which I don't want as I don't like the thought of extra heat pushing back into the loft space. We've pulled the insulation back from the holes where the spots are going but I'm still not happy with the thought of pushing extra heat back there.

Can someone point me in the direction of bulbs for G5.3 12V DIMMABLE halogen spot, not dichroic?? A link would be very gratefully received!

 

[STI]

Hi according to the tec sheet these can be used in a dimmable situation sorry the grammer cells arent working.

http://www.tlc-direct.co.uk/Products/LXAM58G.html

 

[flameport]

Most halogen lamps can be used with a dimmer, but this will significantly shorten their lifespan, particularly if they are used at low brightness for long periods.

We've pulled the insulation back from the holes where the spots are going

Removing insulation will contravene building regulations. So will leaving unsealed holes in the bathroom ceiling.

 

[ban-all-sheds]

And even if you don't care about the Building Regulations you might care about the cold draughts you'll feel coming down from the lights and the condensation you'll get in the loft which will grow mould and rot the roof timbers.

OOI, how big is your bathroom? Is 250W of lighting sensible for a room that size, or is it OTT?

 

[EmyEmy]

STI: Thanks for the link, very much appreciated

Ban-all-sheds & flameport: Bathroom is a good size and with a sloped roof up one side we are restricted on area in which to put them, therefore we're installing directionals in a line so we can 'point' them to areas under the slope (not to mention we like how they look ) I have read quite literally about fifty opinions & articles on recessed spots & insulation, and whilst I'm not worried about building regs as it's my own home (and an old one at that with lots of 'features' that would not be up to code in this day and age! ), I am worried about fire safety and rot...

I considered loft caps but there is a massive beam across the extremely tight loft space which makes a gap just big enough to get your hand through to the ceiling area where the spots are (no chance fitting a rigid loft cap through, and even if there was, there'd be no hope of silicone sticking it down in the layers and layers of fine soot in there, which is impossible to clear).

As for the rot, someone (on this forum I think) offered that as there are vents in our new roof, why would the condensation build up to cause such devastation?

I have literally had sleepless nights over what to do with all the spotlight holes in our newly plastered upstairs ceilings, but it's too late now!

 

[ban-all-sheds]

You'll get condensation because the roof will be cold and the warm moist air getting up there will condense as soon as it hits a cold surface, like the cold timbers, into which it will soak.

If you're happy that the ventilation from the vents will quickly dry wet wood, then go for it.

1 random set of tales about how bad it can get: http://forums.moneysavingexpert.com/showthread.php?t=1390569

1 random photo from a google image search:

 

[EmyEmy]

Thanks for the info and link, I guess I'll go up in to the loft periodically at first to check on it, then experiment with solutions (if any exist?!) if condensation does present itself.

Really wish my electrician had warned me in the first place All he said was to keep insulation away from them, but no mention of any serious problems that it can lead to

 

[electronicsuk]

You'll get condensation because the roof will be cold and the warm moist air getting up there will condense as soon as it hits a cold surface, like the cold timbers, into which it will soak.

If you're happy that the ventilation from the vents will quickly dry wet wood, then go for it.

1 random set of tales about how bad it can get: http://forums.moneysavingexpert.com/showthread.php?t=1390569[/QUOTE]

Bas, did you actually read through that post? I only saw one mention of downlights, and it was quite to the contrary:

PS there is no condensation above either of our bathrooms (one ensuite, one bathroom), one has downlighters, which are exposed for heat safety (although you can seal these with intumescent covers if you wanted too), all the condensation comes mainly on the area above rooms furthest away from those, but the part of the roof which gets the least sunlight in the winter.

Although I couldn't personally recommend installing unsealed lighting into a bathroom roof, I know of people that have done it, and have yet to hear of any condensation issues. I expect that the majority of those that do occur are unrelated to the installation of downlights. That still doesn't change the fact that it contravenes building regs, mind...

 

[STI]

You can get IP65 rated downlighters which come with a seal between the rim of the light and the ceiling . i know the IP rating is more to do with water ingress into the fitting but wouldnt this design also prevent the condensation issue.

They are fire rated to 90mins and the whole body is pretty well sealed from the room its put in.

 

[ban-all-sheds]

Bas, did you actually read through that post? I only saw one mention of downlights, and it was quite to the contrary:

Well I flicked through it, but I wasn't quoting it as an example of downlight related problems, just general "yes you can get condensation in lofts so bad that it drips onto stuff".

Somebody posted on this forum a few weeks ago about condensation he was getting through downlights in a bedroom, IIRC.

 

[EmyEmy]

Since we've already purchased the lights, would a fire hood help at all? (I read these can be installed through the cut hole so no problem there). Would this prevent some of the condensation and/or drafts? I know I can't put insulation over the top of these but maybe it might help a little?

As far as building regs go, what solution do they suggest when recessed lighting is used in loft space? Funny that around 80% of the people on the moneysavingexpert forum got the condensation problems immediately after their lofts had been insulated...

 

[ban-all-sheds]

Because it made their lofts cold spaces. They already had the moist air getting up there, but it wasn't cold.

http://www.nhbc.co.uk/NHBCPublicati...ical/StandardsExtra/filedownload,16553,en.pdf

 

[Stoday]

I'm gobsmacked at the ignorance of basic physics displayed by the contributors to the Money Saving Expert link. Instead of curing the cause they all suggest a bodge (to increase ventilation).

Seems to me that only BAS understands the physics behind condensation in roof spaces.

 

[EmyEmy]

Thanks for the link BAS, I guess we're screwed since there isn't enough space to put anything like described in the regs! Feel a bit let down that our electrician didn't point this out!

 

[ban-all-sheds]

Sadly it is more common than not for electricians to genuinely believe that the only bit of the Building Regulations they have to concern themselves with is Part P.