Putting downlights & dimmers in - what does it entail?

[CluelessDIYer1]

Just an idea that's come to me that i'd like to know what it entails before i look further into it.

We've found a bit of a disaster in our bedroom. Enough to say that the ceiling may need replacing.

Skipping the issues of that problem & focusing ahead - currently there's just a bulb hanging from a cord from the ceiling & there's no dimmer in place...

...what would it take to switch this for downlights & a dimmer? The ceiling would be boarded.

Just so we're on the right page, these are the kinds of lights i'm on about: http://www.diy.com/nav/decor/lighti...ight-H-270mm-x-W-70mm-12258120?skuId=12788826 Those circular ones sunk into the ceiling.

Electrics is way way over my head, so we'd have to get someone in for this. Even the terminology bamboozles me. Is it a big job or nothing?

 

[winston1]

It is not recommended to dim halogen down lights, though people still do it. Halogen lights have to recombine evaporated tungsten in normal operation. This does not happen when they are dimmed so life is short.

That web site mentions transformers and you can't put dimmers on transformers. They may be lying however and they are not transformers at all but switch mode power supplies. Some switch mode power supplies can take dimmers, some can't.

Just a few things to check and think about.

 

[ericmark]

The link tells one very little about the lamps although it says 20W it does not say what type of bulb is used and says it can use a transformer but also says low voltage looked for D033 transformer and all it showed was lights so no idea of voltage would guess 110 volt.

However many of the so called transformers are in fact switch mode power supplies and dimming lamps using these is often a problem there are leading and lagging dimmer switches and these need to be matched to the power supply being used.

As already said quartz is used to keep the envelope at a critical temperature so they should not be dimmer.

So for dimming you have to either use standard tungsten bulbs or very special lamps costing a lot more money. Also with LED often dimming does not alter the colour temperature so does not give the same effect as with tungsten.

Since ceiling is being replaced I would go for two or more circuits. With two circuits one with 1/3 of bulbs and other with 2/3 of bulbs you get three levels of lighting with just two switches and can use cheaper lamps when selecting LED.

I am like many others not keen to spend £10 on one bulb but not so bothered at spending £10 on three bulbs each one then only £3.33 so not a huge bill if one proves faulty.

My bedroom has 5 lights. The original plus two spot lights as some corners dark so 11W CFL plus 2 x 3W LED GU10's also two wall lamps above bed again 3W GU10 lamps so they don't get hot. At door three switches one for main lamp and one each for two spots over bed. Either side of bed a switch for that spot and main light. So no dimmer but I can adjust light in room by how many lights used. All lights are low voltage (230vac) I have not used any extra low voltage lamps just can't see the point in extra low voltage except maybe bathroom.

It is possible B&Q have miss labelled the lamps and they are extra low voltage not low voltage but since no voltage is declared can't confirm this. 12v is called extra low voltage not low voltage.

 

[PrenticeBoyofDerry]

The type of light you have linked to, I believe is more suitable for cabinet lighting than that of a bedroom ceiling.
You would require something more like these.
http://www.anselluk.com/products/TiTAN-and-iCage-Fire-Rated-Downlights/c210

I would steer away from halogen lamps and install LEDs, there are differing types of units out there that will allow you to dim them, some fittings are no composite fitting and everything you need is part of the unit http://gb.auroralighting.com/Lighting-Products/SOLA-i9-Integrated-Fire-Rated-Downlight.aspx, or you could buy seperate units which would include, the cage (fitting) lamp and dimmable driver.

If the ceiling is coming down, I would take this opportunity to make ceiling plan of the joists and any obstructions, note that your fittings will require a minimum specified (manufactures instructions) gap within the void, so check that out prior to selecting the unit.

My rule of thumb for spacing between lights is 600mm within the perimeter then no closer than 300mm and no greater than 1200mm apart, this will be dictated by joists and obstructions in the ceiling void.

Any joints must be made accessible or maintenance free type joints made, the drivers and the fittings would require ventilation, so do not cover with insulation. The dimmer switch should be rated suitable for the load and lighting type.

Then there would also be the relevant building regulations to comply to, such as holing of joists and ingress of fire, moisture and sound.
And the small issue of Part P and BS7671 compliance.

 

[DaftPunk]

It is not recommended to dim halogen down lights, though people still do it. Halogen lights have to recombine evaporated tungsten in normal operation. This does not happen when they are dimmed so life is short.

That web site mentions transformers and you can't put dimmers on transformers. They may be lying however and they are not transformers at all but switch mode power supplies. Some switch mode power supplies can take dimmers, some can't.

Just a few things to check and think about.

It's not recommended by who? I've been dimming halogen lights for years with no detrimental effects what so ever. It's just an old wives tale.

 

[stillp]

I have identical 4-spot (240V GU10) luminaires in my kitchen and utility room. The kitchen has a dimmer, the utility just a switch.
I replace lamps about twice as often in the kitchen as in the utility, in spite of using the lights less in the kitchen.

 

[bernardgreen]

It's not recommended by who? I've been dimming halogen lights for years with no detrimental effects what so ever. It's just an old wives tale.

SOME halogen lamps can be dimmed without a significant reduction in life but NOT all.

The life span on dimming depends on lamp construction, the halogen additive used and whether dimming is normally expected for this type.

 

[ericmark]

With the use of halogen lamps to get around the daft restrictions for combining heating and lighting into one unit I am sure some are designed that can be dimmed. In the early days we bought the bulb with no built in protection now we by a lamp where the quartz is contained within a second glass envelope to retain the hot bits and harmful rays from these lamps.

However splitting the heating and lighting does help in our short summers and I for one do not want the ritual of swapping bulbs summer and winter although I must admit the radiated heat from the heat emitting bulbs does reduce the ambient temperature required to make the room feel comfortable so there will be a point where tungsten bulb save energy however this will depend on number of air changes in the room and if heat recovery units are used. I did ask the energy saving trust at what number of air changes the tungsten bulb would be more energy saving than the CFL at that time LED lamps were not in common use. However in spite of a huge drive including the removal of 100W pearl bulbs from the market place they said no survey or tests had been done so it would seem the removal of tungsten bulbs was just to create a market and boost the economy and nothing to do with energy saving.

In the same way use of quartz and halogen in lamps would mean all these bulbs have a very white light and very good for replacing bright sun light. However in a bed room I would want a lower colour temperature even the 3000K warm white I bought are really too white for a bedroom. I would really be looking more around the 2500K or less for a bedroom which means any quartz halogen lamp is out.

 

[CluelessDIYer1]

I'm on my break on my phone. Just to say thanks for the replies - I'll read them tonight after work.
Just on skimming there appears to be confusion. I wasn't meaning that exact light. Maybe I should've linked an image instead as I just meant for it to show them circular lights you get in the ceiling, not any specific light/brand etc.