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I am looking into buying some 5W LED 3000k GU10 spotlights with a rating of 450 lumens, for my gypsum soffits. The only part which is confusing me is what viewing angle I should get. I have found a lot for sale with a viewing angle of 60 degrees, 90 degrees or 120 degrees. However I am not sure which to opt for. At the moment, the best deal which I found is on a viewing angle of 120 degrees. Would it be a good choice?

Below is a plan of how my spotlights are laid out. The main bedroom already has 4 spotlights which are not shown on the plan.

Would 120 degrees work for these rooms? Or else, should I get different viewing angles for different rooms?

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    How tall are the ceilings? – mmathis Oct 24 '17 at 16:08
  • Ceiling height and light spacing are important to answer this question. – JPhi1618 Oct 24 '17 at 19:03
  • Ceiling height is around 2.6m – MathLover Oct 26 '17 at 10:25
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How long should a rope be?

There is no right answer, it all depends on what you want, and how much space you are lighting. Generally speaking, spot lights will create a more dramatic scene, while floods create a relaxed casual feel or uniformly bright work area, depending on intensity.

if the fixtures pivot/tilt somewhat, spotlights can be used towards a wall to highlight a piece of art or family photograph. A lot of people still like straight-down spotlights in the hall, it tends to make space look bigger, and uniform lighting is not important in an area you don't stay in. Floods in the hall will work just fine, you just won't have the six bright spots on the flooring as you look down the hall.

In the bedrooms, you probably want those to be floods to create a smooth uniform calming light. However, you don't have to be homogeneous, especially if you have 6 fixtures. You can put out a lot of light with 6 LED bulbs. One of those can be a smaller angle to create a (slightly) more intense light on a desk, reading chair, or decoration.

TLDR: use 120s except for effect.

  • So what you're saying is that 120 degrees are suitable just for general lighting in a room? As I have found many resources which recommend 45 to 60 degrees for this, however when looking up well-rated LED GU10s on Amazon UK, almost all of them are 120 degrees. So it's not easy for me to find 45-60 degree examples. – MathLover Oct 24 '17 at 9:05
  • some people like dramatic lighting. 45 for general lighting seems like overkill to me, unless you're at a museum or have high ceilings. For task lighting, or in a kitchen, well-placed spots can be a godsend. – dandavis Oct 24 '17 at 9:23
  • So for the corridor and bedrooms the lighting should be sufficient at 120 degrees? – MathLover Oct 24 '17 at 9:24
  • I think it will look fine, if maybe a little uneventful. Spot lights are harder to dim while keeping consistent minimum illumination ,and I dim a lot, so i might be biased. To me, the best lighting isn't noticed. You might buy a few cheap bulbs (halogen, cfl) of different angles, just to preview the effect with a portable lamp. – dandavis Oct 24 '17 at 9:34
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Angles are a thing. Use them.

The great tragedy of lighting -- up until LED -- is that every bulb emits a sphere of light. That is fairly useless. Everyone wants a wedge of light to illuminate whatever they're trying to light up. Refelectors try to put some of that to use, but reflectors don't perform well.

If you've ever seen one of those metal halide barn lights, half their light goes to wildly overlight the side of the barn they're attached to. What's the point of that? It is wasted light!

The advantage of LEDs is they naturally light about a 160 degree wedge, and it's easy with lenses to focus that much more narrowly. Lenses are much more efficient than reflectors.

So you've given us a horizontal diagram, now you need to diagram this out in the vertical dimension. What is below the lights? What wedge of light do you want from each lamp? The angle of the wedge is the angle of the lamp to buy.

For instance, a 60 degree light will spread to create a circle about the same diameter as its height above the surface. (Well 1.15x to be precise). And half that as their radius. So some of your lamps are 900mm (3 foot) away from the wall: if you wanted to light the floor, and the lamps are 2.2m above the floor, then the disc of light will be about 2.2 metres in diameter, or 1.1 in radius, slightly bigger than their distance from the wall. So a 60 degree light there will light the floor effectively, and waste little energy lighting up the wall.

Whereas on those lamps 300mm from the wall, they will throw a lot of light on the wall even with a 60 degree light... unless they can be aimed away from the wall. It would help a lot if they were lighting up a surface much higher than the floor, like the top of a row of dressers, maybe with a mirror.

  • Wow, this is so much more complicated than I thought. Any idea why most of the ones for sale seem to be 120 degrees? – MathLover Oct 26 '17 at 10:22
  • Also, Ceiling height is around 2.6m. – MathLover Oct 26 '17 at 10:25
  • @MathLover why do stores put things on sale? Because they feel they can't get full price for them. Why can't they? Ding ding ding. – Harper Oct 26 '17 at 15:53
  • So now that I've provided the vertical height, does that help to suggest what viewing angles to go for? – MathLover Oct 27 '17 at 10:05

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