12v or Mains voltage lighting for kitchen?

[Drongo]

I’m putting new recessed down lights in my smallish (15’ 6” x 11’ 6”) kitchen.

The lighting will go into the ceiling void. There is (if it’s relevant) a room above the ceiling.

I’m not a practical person (that’s quite an understatement! ) so I’ve several questions to ask. Please reply in the simplest possible terms.



1) How many lights would be I need for this area of kitchen? I guessing that nine 50 watt lights would be about right; arranged in the rows of three; either each row independently switched or one row of three independently switched and the other two rows both switched together.

2) Should I go for mains voltage or 12v lighting? What are the pro’s and cons? I was leaning toward mains voltage lighting as I didn’t fancy the idea of a bulky buzzy transformer. However it seems as if my idea of 12v lighting is somewhat outdated. I understand that it’s now possible to get recessed lights where the compact transformer sits atop the light unit itself. So what type to go for?

3) Fire hoods. I’m told that the light fittings now are usually fire righted and that they sit in a metal can that acts as a firehood and that there is no need to install a separate fire hood. Is this correct?

4) What type of lighting should I use. There seems to be a bewildering choice of lighting types. I’m leaning towards Halogen lights. I’ve got them fitted elsewhere in the house and I like the type of light they produce.

However I understand that you can also get LED and CFL types. The few LED lights I’ve seen seem far too dim despite their rated wattage and the light seems ‘cold’ so they don’t appeal. I know nothing about CFL lights and so I’m at loss as to which type to go for.



Any help or advice very gratefully received!

[MarkP80]

Hi Drongo,

I'll kick off with a few ideas of my own, I'm sure more people will contribute with different ones, to get you a discussion going. First of all though, don't forget you are a) talking about electrics in a kitchen, and b) not simply swapping as light fitting over, so this falls under specific Part P requirements - I'd recommend you get an electrician to do the work and get all the appropriate certification. So, as to your questions -

1) For a room that size I'd expect six 50w 12v halogens would be more than enough. Don't forget the apparent ceiling area is reduced by the wall cupboards.

2) You can get transformers that don't buzz when dimmed, I've used them before. Slightly more expensive than standard, but worth it I think. Have a look here for the transformers I used. I would personally recommend 12v rather than mains, you do get better bulb life, but I'm sure you will get as many people saying go for 230v.

3) Yes, you can get fittings which are fire rated, have a look on the TLC website, you'll see them there. (This page includes fire rated lights)

4) I like halogen light, that's what I'd go for personally, but let's see what others advise.

HTH,
MarkP

[Sonic67]

I'd go for 240v, less to go wrong. If you go for 12v how accessible will the transformer be?

[paul_62]

always personal preference about what voltage, i think 230v as then you dont have a issue of changing transformers should 1 blow (not hard to change they simply pull through the hole the light was in sonic) - not realy a great expense or time consuming but everything adds up, i prefer to fit them then forget all about them.
i'd also look at the low wattage cfl they do a gu10 version, i've changed a few over the years and have noticed halogens give a yellow light and the low wattage give of a cleaner white light, their not the best on a dimmer as they seem to be a stepped dim which you wont notice unless you sit there for ages to test just because i mentioned it
LED lights are getting better but personaly i only use them for plinth or under cabinet lights where they are 'mood' lights yes they do seem cold but they are getting better and its all down to cost they will be retro fitable against gu10's
not sure how this site works with advertising but the web site metioned by mark is one of the cheapest and i use it a fair amount
always go for fire rated this is about building regs and slowing down the spread of a fire.
as for distance generaly 1m apart gives a good spread of light it all depends on the location and direction of the beams and obviously how much 'ocd' you have with the distances apart
yes it is 'notifiable work' so you will either have to apply for planning permision and get the council to check it afterwards this will cost about £60 - and unless your extremely competant with a sound knowladge of the regs and the rest of your house is up to current standards i'd avoid this.

[silver12]

Originally Posted by MarkP80

Hi Drongo,

I'll kick off with a few ideas of my own, I'm sure more people will contribute with different ones, to get you a discussion going. First of all though, don't forget you are a) talking about electrics in a kitchen, and b) not simply swapping as light fitting over, so this falls under specific Part P requirements - I'd recommend you get an electrician to do the work and get all the appropriate certification. So, as to your questions -

1) For a room that size I'd expect six 50w 12v halogens would be more than enough. Don't forget the apparent ceiling area is reduced by the wall cupboards.

2) You can get transformers that don't buzz when dimmed, I've used them before. Slightly more expensive than standard, but worth it I think. Have a look here for the transformers I used. I would personally recommend 12v rather than mains, you do get better bulb life, but I'm sure you will get as many people saying go for 230v.

3) Yes, you can get fittings which are fire rated, have a look on the TLC website, you'll see them there. (This page includes fire rated lights)

4) I like halogen light, that's what I'd go for personally, but let's see what others advise.

HTH,
MarkP

All of the above is perfect advice. One note however - ANY work, however small, in a kitchen or bathroom is notifiable under Part P of the Building Regulations, and it would be against the law to contravene it.

However, if you are a good DIY'er, and know someone who will test the work for you afterwards then I see no reason not to carry out the work yourself.

Always try to remember that electricity is as dangerous as gas, yet noone would ever work on gas unless they felt 100% confident, ensure your confidence is the same with electrics.

If you fit a fire rated fitting then it will also solve this problem, however if you don't and intend to fit fire hoods/fire blanket instead then:
You must also ensure compliance with multiple parts of the Building Regulations, your light fittings will have to comply with Part E, passage of sound. If you fit a non fire rated fitting then not only will you need to fit a fire hood you will also need to build a box around each light fitting to ensure the passage of sound is no worse than it was before the light was fitted.

In short - always fit fire rated fittings for an easy life.

It also may be worth asking a friend if they have an account at a wholesaler, as I pay £4.10 per fitting, rather than TLC's inflated prices.

[Drongo]

Thanks every body for your kind replies; they are very much appreciated.


Your answers have prompted a few more questions:

Originally Posted by MarkP80

“First of all though, don't forget you are a) talking about electrics in a kitchen, and b) not simply swapping as light fitting over, so this falls under specific Part P requirements - I'd recommend you get an electrician to do the work and get all the appropriate certification.

Don’t worry; the work will be done by a qualified electrician. Tying my shoelaces is as ‘practical’ as I get.

Originally Posted by MarkP80

1) For a room that size I'd expect six 50w 12v halogens would be more than enough. Don't forget the apparent ceiling area is reduced by the wall cupboards.

Thanks for that.


So my idea of having nine 50w down lighters is overkill?


Although I suppose if I went for three rows of three light; each row independently switched; I could simply switch off one row if it was too bright.


If I did go down the mains voltage route for the lighting and I found it was too bright; could I simply change some (or all) of the lamps for 35w or 20w ones?

Originally Posted by MarkP80

12v rather than mains, you do get better bulb life, but I'm sure you will get as many people saying go for 230v.

I think the deciding factor for me is which one (mains voltage or 12v) will produce less heat in the ceiling void.


I’ve read through THIS thread.


Post number 25 seems to suggest that the heat generated by low voltage could be considerable in the void behind the lamp.

Originally Posted by Zog

The issue with heat is an interesting one. The vast majority or the LV lamps are "dichroic". This refers to a coating on the back of the lamp which allows light at the red end of the spectrum to pass right through, but reflects the rest back out of the front glass. The light that passes through back of the lamp also contains the heat. This is great as it keeps the beam relatively cool, but complicates matters as the heat is therefore contained within the ceiling void. 50 watt lamp produces approximately 45 watts of heat, maybe more, this has to be handled with care. Hence the need to clear away all insulation etc. Make the light fitting with cr@ppy components and/or design on the cheap and it wont be able to manage the heat. Consequently in the best scenario, the lamp will probably fail prematurely, worst case, set your house on fire.

In comparison, the 240 lamps have no such dichroic coating. They are a straight forward silvered glass reflector. All the light including the heat is emitted from the front of the lamp. In practice this makes things a lot simpler for mounting as there is less heat to deal with. However in reality, the lamp itself tends to run hotter and within a cheaper fitting this is very dodgy.

Overall..... as a professional lighting designer, its 12 volt everytime.

Better quality, crisper light.

More flexibility to fine tune the installation by varying the wattage and beam angle.

Vastly increased lamp life, offering cost savings on maintainance.

Is this right? If that was case I think I’d prefer to go with mains voltage lights.

Originally Posted by paul_62

i'd also look at the low wattage cfl they do a gu10 version, i've changed a few over the years and have noticed halogens give a yellow light and the low wattage give of a cleaner white light, their not the best on a dimmer as they seem to be a stepped dim which you wont notice unless you sit there for ages to test just because i mentioned it

Do you need a specific light fitting for CFL GU10 lights?


If I fitted mains voltage halogens could I simply swap the lamps for CFL lamps later on or would I need to change the entire fitting?

Originally Posted by paul_62

always go for fire rated this is about building regs and slowing down the spread of a fire.

Originally Posted by MarkP80

Yes, you can get fittings which are fire rated, have a look on the TLC website, you'll see them there. (This page includes fire rated lights)

Originally Posted by silver12

In short - always fit fire rated fittings for an easy life.

Thanks; I will use fire rated light fittings.


So if a light fitting is fire rated; there is no need to install a fire hood?


What I don’t fully understand is how they work. I believe that in the event of a fire; a fire retarding material expands to fill the void in the ceiling to prevent fire spreading upwards.


What I’m not sure about is whether the heat from the lamp is better ‘shielded’ than with a non fire rated light fitting? Will using a fire rated light fitting mean that less heat goes up into the void?


Once again; many thanks for your help

[silver12]

Yes, it is ok to reduce the wattage of one or more lamps. I personally would consider using a CFL lamp - a decent wholesaler will let you borrow one to try out overnight and then you can make an informed choice. CFL lamps are a retrofit item, they will fit in any GU10 fitting.

If I were fitting downlights and had to use halogen lamps then I would fit 230V ones, simply to reduce the need to fit a transformer at every light - time and cost!

Fire rated fittings tend to get a little hotter than normal ones, but the newer style ones do a better job of directing the heat downwards. The job of a fire rated fitting isn't to run cooler, it is to ensure that in the event of a fire, the fire does not spread as quickly.

You are right in your assumption that a fire rated fitting will negate the need for a fire hood.

[Drongo]

Originally Posted by silver12

Yes, it is ok to reduce the wattage of one or more lamps. I personally would consider using a CFL lamp - a decent wholesaler will let you borrow one to try out overnight and then you can make an informed choice. CFL lamps are a retrofit item, they will fit in any GU10 fitting.

If I were fitting downlights and had to use halogen lamps then I would fit 230V ones, simply to reduce the need to fit a transformer at every light - time and cost!

Fire rated fittings tend to get a little hotter than normal ones, but the newer style ones do a better job of directing the heat downwards. The job of a fire rated fitting isn't to run cooler, it is to ensure that in the event of a fire, the fire does not spread as quickly.

You are right in your assumption that a fire rated fitting will negate the need for a fire hood.

Thanks.

I’ve been having a rethink about my original idea.

The more I’ve read; the more I’ve become concerned about potential hazards caused by heat build up in the ceiling void if I recess Halogen down lighters.

The new plan is to put four 11w (i.e. 50W incandescent equivalents) recessed CFL down lighters into the ceiling and I would also surface mount a track with four mains voltage 50w Halogens.

The CFL’s and the Halogen’s would be separately switched.

I’m thinking that the CFL’s won’t have any problems with regard to heat build up and that the slow warm up time of the CFL’s would be negated by the fact I would have instant light from the Halogen’s.

Thoughts anybody?

[neilball]

If you are using fire-rated downlights then you have to use them with an aluminium reflector lamp which passes all heat forward into the room and not let the heat pass back through the lamp reflector into the ceiling (which a standard halogen lamp does). As long as the transformer (as I prefer 12v fittings) is not right on top of the fitting and the ceiling is not fully insulated then it would be fine.

[aamuk]

I also prefer 12V fittings, but I also have a problem with the amount of heat produced by them.

I did try led based 12V MR16 lamps a couple of years ago as they produce very little heat and consume a fraction of the power, but what I found was that the light was more suitable for accent lighting rather than main lighting. I haven't really looked at them again recently, but I have been told that the technology is getting better, where soon they will be suitable as real replacements for traditional halogen lamps.