Lighting for beamed ceiling?

[oldstuff]

Hi,

Does anyone have any bright ideas (pun intended) for lighting on a beamed ceiling? I guess I will have to use some kind of spots bolted or screwed to the beams but can’t seem to find any decent websites with what I am looking for!

I want them to be as unobtrusive as possible but the ceiling is quite low at maybe 7-8ft.

TIA

 

[skier-hughes]

Wall lights, very handy in low ceiling rooms.
Are you looking for modern or old style?
Try these
http://www.broughtons.com/products.php?cat_id=505

 

[Flyfisher]

Our old kitchen has a fairly low beamed ceiling and it has a couple of 5-foot fluorescent tubes between the beams.

Their good points are that they provide very good, even lighting and they don't lower the headroom. Fairly ideal for a kitchen.

Their bad points are that they are, er, fluorescent tubes. Fairly awful-looking for anything other than a kitchen/utility room.

I would agree with the wall-light suggestion, although these can also be problemmatic if mounted too low because they can be easy to bump into , depending on positioning and other furniture in the room.

Table and/or standard lamps?

 

[vicky whitworth]

Jim Lawrence does some nice small spot lights I noticed the other day in a sort of bronzy colour. I'm thinking of changing the ones I bought for my low ceiling kitchen which although the tiniest I could find at the time are hardly 'period'.

 

[Moo]

I'm pretty sure that we had a thread about this problem not that long ago.
A number of useful possible solutions emerged, but each had their good and bad points, like Flyfisher's fluorescent tubes, and in the end the concensus was that table and/or standard lamps wired to a single switch near the door was the simplest and most effective solution.

 

[Moo]

Apologetic PS

That was a rather silly suggestion of mine, wasn't it? Please ignore it. Table/standard lamps wouldn't be very practical in any of the kitchens I've seen.

 

[christianb]

the ceiling is quite low at maybe 7-8ft.

Luxury! The headroom in the downstairs of mine is 6'3".

Anyway, I had the same problem and solved it by picking up some small, plain, spots on special offer at a well-known diy retailer. Great things as you can create some really charcterful lighting and can't actually see them unless you're directly below!

C.

 

[Flyfisher]

That was a rather silly suggestion of mine, wasn't it? Please ignore it. Table/standard lamps wouldn't be very practical in any of the kitchens I've seen.

Don't chide yourself Moo. The original question didn't mention a kitchen - that was just my example.

 

[FamilyWiggs]

Besides - we have two table lamps in our kitchen! They sit on the work surfaces and make much nicer (and cheaper) light in the evenings rather than the halogen spots ( :shock: ).

Incidentally (and I should know this from schoolboy physics) are the 12v 50w lamps cheaper to run than the 240v 50w lamps? SWMBO asked at the weekend, given that the electrickery bill is measured in units which are kilowatt hours. I ummed and ahhed and then found a reason to retreat to the shed for something important...

I know W = A x V, so I presume they are - but then both are 50w bulbs so do they consume watthours at the same rate? :?:

 

[Flyfisher]

If the 12 volt transformer supplying the halogen bulbs was 100% efficient then both 50W bulbs would draw the same amount of power from the mains supply.

Unfortunately, it can't be 100% efficient so although the halogen bulb will only use 50W of power there will also be some power consumed in the transformer supplying the 12 volts. The amount of power 'lost' in the transformer (not really lost of course, mostly turned into heat) will depend on the technology used. A modern design could easily be 90% efficient, maybe more (I'm a bit out of date these days).

So, assuming 90% transformer efficiency, the 50W halogen bulb will actually draw 50 / 0.9 W of power from the mains = 55.6W, i.e. they'll be more expensive to run than a 50W mains bulb.

 

[chuckey]

Flyfisher, you are not comparing like for like. Halogen bulbs give out 30 Lumens per watt against 20 for filament bulbs, so it would be better to compare 30W Halogens to 50W filament bulbs cos' they should give out about the same amount of light. However Halogen bulbs tend to be focussed. (CFL = 50+ L/W, new LEDs 70 L/W)
Frank

 

[Schoolmarm]

:?

 

[chuckey]

In my beamed sitting room (90" height to under beams), I have a stubby chandelier and wall lights.
Frank

 

[Flyfisher]

Flyfisher, you are not comparing like for like.

I was just answering the question as posed by FW, i.e. are the 12v 50w lamps cheaper to run than the 240v 50w lamps?

I did think about mentioning that the bulbs themselves had different efficiencies in converting electrical power to light but thought it would be a digression too far - unusual, I admit.

 

[AMc]

Incidentally (and I should know this from schoolboy physics) are the 12v 50w lamps cheaper to run than the 240v 50w lamps? SWMBO asked at the weekend, given that the electrickery bill is measured in units which are kilowatt hours. I ummed and ahhed and then found a reason to retreat to the shed for something important...

I know W = A x V, so I presume they are - but then both are 50w bulbs so do they consume watthours at the same rate? :?:

Power = Current x Voltage (P=IV) only works on DC if memory serves and AC is more complicated. The 12v bulbs require an AC/DC conversion as well as a voltage step down, they will also lose more lighting power as heat in the cabling (lower voltage=higher current). Obviously the fact that they use thinner cable can make installation easier but I can't see how they could be more efficient in turning power at the switch into light in the room?

In the end I suspect there will be very little practical difference the bulbs are probably more important in terms of power consumption and light output than the 12V or 240V supply.

As chuckey alluded to the lumens per watt is more important than the wattage per se. Your could theoretically have a 100W bulb that produced no visible light (e.g. a UV 'black' light) or a 5W LED bulb that produced more light than a 20W halogen. Higher lumens per watt makes for brighter light from the same power input, then there's colour temperature...

IMHO you're better off with the 240V G10 fittings as there are fewer things to go wrong. When we had the 12v variants I replaced several transformers some of which had melted quite a lot before failing :shock:. I think you'll have an easier time replacing 240V G10 bulbs with high output LEDs as that technology comes to maturity without needing to replace the fittings. Low voltage LEDs come with their own transformers so I doubt you could directly swap the bulbs without also changing the fittings and transformers.

I would only go for 12V fittings if I could hide the transformer but needed the thin wire for installation, under counter lights with no pelmet for instance.

 

[Flyfisher]

Power = Current x Voltage (P=IV) only works on DC if memory serves and AC is more complicated.

AC can be more complicated, due to the power factor associated with inductive loads, but lamps are essentially simple resistive loads so P=IV works OK.

The 12v bulbs require an AC/DC conversion as well as a voltage step down, they will also lose more lighting power as heat in the cabling (lower voltage=higher current). Obviously the fact that they use thinner cable can make installation easier but I can't see how they could be more efficient in turning power at the switch into light in the room?

I've not used 12V tungsten lamps, but is there any reason why they can't run on AC?

Also, do they really use thinner cable? As you rightly say, for a given wattage, a 12v lamp will draw more current than a 240v one. Indeed a single 12v 60W lamp will draw 5A, or the same current as an entire mains lighting circuit. I suppose the low voltage means the cable need not be double insulated, but the basic conductor must be capable of carrying much higher currents than mains lighting.

As for efficiency, I believe these low-voltgage lamps are more efficient at generating visible light because of their tungsten/halogen construction rather than being low voltage per se. Tungsten/halogen bulbs can run hotter (without reducing their lifetime), which makes them more efficient at converting electrical power to light than 'normal' light bulbs that use an inert gas.

 

[philpjuk100]

Yes halogen are filament lamps and will run on ac or dc,it is led lighting which uses polarity sensitive dc.

 

[MdB]

Also, do they really use thinner cable? As you rightly say, for a given wattage, a 12v lamp will draw more current than a 240v one. Indeed a single 12v 60W lamp will draw 5A, or the same current as an entire mains lighting circuit. I suppose the low voltage means the cable need not be double insulated, but the basic conductor must be capable of carrying much higher currents than mains lighting.

Exactly right. 12V lights need cable that is more than 20 times thicker (cross sectional area) than the same wattage 240V bulb. This goes for the rating of any switches in the system as well. Some people recommend using old style switches for low voltage systems as they aren't safe to use for high voltage. Unfortunately, due to the increased current requirement they aren't suitable for low voltage either and could potentially cause fires

Yes halogen are filament lamps and will run on ac or dc,it is led lighting which uses polarity sensitive dc.

If you know what you are doing you can run LEDs off AC as well as DC but it isn't completely straight forward.

 

[philpjuk100]

This is because the leds are diodes and "rectify" eg turn ac into dc but all the led transformers I have use a rectifier and give a dc output.

 

[AMc]

Interesting comments - my experience of 12V Halogen recessed downlighters was a while ago and IIRC they had AC/DC step down transformers inputs labelled as Live and Neutral and outputs as + and - . I could be wrong I stand by them as a point of failure I would work to design out when the transformers are hidden in the ceiling.

My comment on cable thickness was based on removing the pyramid shaped 12v under counter lights in the last kitchen (which were carp BTW). The connecting cable was substantially thinner than 2.5mm twin and earth and allowed the previous bodger to feed cable through the insides of the cupboards and out underneath - handily putting plug in connector blocks unprotected on the shelves at the back of high level cupboards where the connectors got bashed by cans and boxes . That lead to them failing all the time, coming on and off by themselves and many other merry dances. I suspect that the thinner cable can be used because the length of cables are precut and the ease of installation is balanced against the loss in efficiency in heat from the cable. A 12v loop of the same length as a standard lighting circuit would be a terrible idea.


To then massively contradict myself and in the hopes of dragging the thread back on topic...
Given that ceiling lights are not contemporary with beamed ceilings I would go for something modern and unobtrusive. I'm guessing you don't have a void between the ceiling and the floor above to hide recessed spots or route cables?

Having railed against 12v systems I would seriously consider the cable mounted systems like this one
http://www.ikea.com/gb/en/catalog/products/90120456
You can attached the cables from one side of the room to the other between the beams, position the lights and angle them how you want. The cables more or less disappear esp. when the lights are on and (with that one) add between 4 and 10 lights on a single run.

In general I found looking for lights a major chore. Most were ugly and too expensive or ugly and really expensive In the end we've used some Tom Dixon end of line (reduced from obscene to ridiculous) intermixed with cheapo lighting from IKEA and Habitat (a distinction with little difference). Our vinery has £200 wall lights from TD and £5 pendants from IKEA. Our kitchen has a load of building control compliant low energy spots which work fine in a basically modern room and a nicer glass pendant over the table from IKEA.

At the very least I find IKEA lights well made and decent valye for money
http://www.ikea.com/gb/en/catalog/categories/departments/lighting