38 deg or 60 deg beam angle for LEDs in small rooms?

[jayjon]

Hi, I'm replacing down lights in my very small kitchen (3m x 2m) and two small bathrooms (2m x 1.5m and 3m x 2m).

I'm just re-using the existing holes; 3 in the kitchen and larger bathroom, 2 in the small bathroom.

The LEDs I like come with either 38deg or 60deg beam angle. Does anyone have any recommendations which please? I was thinking 60deg so the light is more evenly distributed but this is just a complete guess on my part.

Any help appreciated,

JJ

 

[securespark]

Ever since the introduction of SELV lighting (and its subsequent variations) in the 1980's, I have tended towards using 60 degree floods (although the 38 degree lamps are also labelled "flood").

Whether tis nobler in the mind, I mean whether tis better with 60 degrees or not I'm not sure.

RF???

 

[ericmark]

To me two ways of lighting a room.
1) Direct
2) Bounced or reflected.
With spots the idea is to bounce or reflect light off light surfaces however in some installations the copying of the idea has clearly gone wrong with no light surface to bounce the light off.

If lights are aimed to reflect off a light surface then tight beams will likely work best if however it's a poor copy and there is no light surface the wide angle will work better.

 

[bernardgreen]

the light will cover a circular area. Important when considering the illumination of a working area such as a kitchen surface. People working will cast shadows on the worksurface and on the tools being used.


The diameter of the primary area depends on the beam angle and the height of the lamp above the surface to be illuminated. The edges of the area are often diffused as the light source is seldom a single point but has multiple reflections from the reflector in the lamp housing.

The diameter of that circular area can be calculated using trignometry

The radius of the primary area is the height multiplied by the tan of half the beam angle. The diameter = twice the radius

For a 30° beam
tan of 15° = 0.268
radius = h * 0.268
diameter = h * 0.536


For a 60° beam
tan of 30° = 0.577
radius = h * 0.577
diameter = h * 1.154

 

[JohnW2]

The diameter of the primary area depends on the beam angle and the height of the lamp above the surface to be illuminated. The edges of the area are often diffused as the light source is seldom a single point but has multiple reflections from the reflector in the lamp housing. ... The diameter of that circular area can be calculated using trignometry ... The radius of the primary area is the height multiplied by the tan of half the beam angle.

Indeed so - but, as eric has sort-of implied, the problem is that, in terms of general domestic lighting, it is often/usually not obvious what 'surface' one is interested in being the primary target of the illumination (hence what value of 'height' to use in your calculation).

Pragmatically, if the wish/intention is to light an entire room (as opposed to specifically illuminating a single object, for which one would use a narrow beam angle spotlight) as 'evenly' as possible, it would seem (at least to me) to make sense to use a lamp with as wide a beam width as one can find.

Kind Regards, John

 

[jayjon]

Thanks for the replies everyone. There isn't a specific area I want lighting, more just an even (as possible) spread around the room.

I think I'll go for the wide angles.

Thanks for the help, I appreciate it.

JJ.

 

[ban-all-sheds]

Thanks for the replies everyone. There isn't a specific area I want lighting, more just an even (as possible) spread around the room.

In that case you do not want torches recessed into the ceiling.