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Beam angle and spacing: the calculation contractors ignore
“Just put a spotlight every two metres” sounds practical, but it ignores ceiling height and the fitting's angle. A correct layout starts with two questions: what do I want to light, and from what height?
Angles and their names
| Angle | Common name | Use |
|---|---|---|
| Less than 15° | Narrow Spot | Artworks, small paintings, façade columns, very high ceilings |
| 15° – 25° | Spot | Tables, feature walls, double-height spaces |
| 25° – 40° | Medium | General lighting under standard ceilings |
| More than 40° | Flood / Wide | Corridors with low ceilings, wide general lighting |
Proven layout rules
- Spacing between spotlights is based on the mounting height: many manufacturers state the spacing-to-height ratio (Spacing Criterion) on the specification sheet, typically between 0.5 and 1.5.
- The distance between the first row and the wall is about half the spacing between fittings.
- A Wall Washer sits about a third of the room height away from the wall, and the spacing between washers should not exceed one and a half times their distance from the wall. Under ceilings higher than 8 metres, the distance can drop to about a fifth.
- Lighting paintings and sculptures: an angle of incidence of about 30° from vertical reduces reflections on the glass and prevents a frame shadow.
- In double-height spaces, light from wide beams doesn't reach the floor; use narrower angles and higher lumens.
Choosing the angle for accent lighting
To keep the light on the object alone, choose the angle from the object's size and its distance from the fitting. The table shows the approximate diameter of the light spot for each angle and distance. Example: a vase 25 cm wide on a table 75 cm high under a 2.75 m ceiling, i.e. 2 m from the fitting: the right angle is between 5° and 10°.
| Beam Angle | At 1 m | At 2 m | At 3 m |
|---|---|---|---|
| 5° | 9 cm | 17 cm | 26 cm |
| 10° | 17 cm | 35 cm | 52 cm |
| 24° | 43 cm | 85 cm | 128 cm |
| 36° | 65 cm | 130 cm | 195 cm |
Lighting paintings on a wall
- The fitting's distance from the wall is about half the distance between the ceiling and the centre of the painting, so the light falls at an angle close to 30°. In a room about 3 metres high, this is usually between 75 and 85 cm.
- Any closer, and the light grazes the wall, leaving a bright spot above the painting and a frame shadow. Any further, and the light reflects off the painting's glass into the eyes of someone standing in front of it.
- Choose the angle from the size of the painting: very narrow for a small painting, medium (about 24°) for a large one.
- A recessed spotlight usually tilts only up to 30°, while a track spotlight moves freely and suits places where the paintings change.
When form matters more than the grid
An even grid layout looks tidy on the drawing, but it lights the floor evenly and leaves the walls and important features undistinguished. Good design puts light where the eye goes: on walls, seating areas and features, leaving calmer zones. Fewer fittings in a considered layout often give a more beautiful result and a cleaner ceiling.
Adjustable beam angle (Zoomable)
Some fittings let you change the angle by hand after installation, for example from 15° to 60°. Useful for track systems, showrooms and spaces where the furniture changes.
Related mistakes and comparisons
Common mistakeFacade lighting and windows
“You installed powerful floodlights on your villa facade, but the light hits the windows and keeps you up at night?”
- The problem
- Aiming facade lights at a wide, random angle lets light spill into the bedrooms.
- Technical explanation
- Exterior lighting needs a very narrow beam and precise aiming (Narrow beam) so it lights only the architectural details without causing disturbance.
- The result
- An eye-catching, elegant facade, with complete calm and comfortable darkness inside the bedrooms.
Common mistakeThe facade-lighting mistake of mounting flush to the wall
“Want your facade light to throw a stunning beam? Don't mount it flush against the wall!”
- The problem
- Mounting wall lights flush against the wall creates a harsh, very distracting Hotspot that spoils the facade.
- Technical explanation
- Moving the fitting slightly away from the wall and choosing the correct aiming angle gives a long, ideal beam that highlights the villa's height up to 16 m.
- The result
- A facade that catches the eye of the whole neighbourhood, at low cost and with smart installation.
Common mistakeOverdoing outdoor lighting (Floodlights)
“Installed stadium floodlights on your villa facade? You haven't lit it up, you've washed out its features!”
- The problem
- Flooding the facade with wide light erases the architectural details and creates light pollution.
- Technical explanation
- Highlighting a facade needs a well-planned layout of upward and downward Spotlights with narrow beams to create “contrast” between light and shadow, because shadow is what reveals the beauty.
- The result
- A palace-like facade with a far smaller electricity and installation budget.
Common mistakeLight pollution and disturbing the neighbours
“Installed lights on your home's facade, but the light reaches your neighbour's bedroom?”
- The problem
- Aiming outdoor lights at wide, random angles causes light pollution and disturbs the surroundings.
- Technical explanation
- Using outdoor lights with a narrow beam (Narrow Beam <15°) keeps the light on the facade column only, without spilling into windows.
- The result
- An elegant, well-defined facade, and complete comfort for your family and neighbours.
Common mistakeRandomly placed bollard lights
“Has your garden turned into an airport runway because of your path lights?”
- The problem
- Placing bollard lights too close together, randomly and excessively
- Technical explanation
- The ideal path bollard is spaced every 4 to 5 metres, and its height should ideally be half the width of the area being lit
- The result
- Elegant, calm garden paths with no extra fixture costs
Common mistakeChoosing the wrong wattage for façades
“Want your villa façade to stand out from afar? Don't fit it with a 5 W light!”
- The problem
- Using very weak Grazer fittings for tall façades.
- Technical explanation
- A tall façade needs a 36 W fitting (about 2300 lm) to reach the top of the building, while 5 W (300 lm) is left for soft lighting of lower walkways.
- The result
- A palace façade that catches the eye of the whole neighbourhood.
Comparison5° ground Up-light
“Lit up your façade and all the light shot off into the sky?”
- The problem
- Using wide ground lights for tall columns
- Technical explanation
- Tall, slim columns need a very narrow Beam Angle (5°–10°), almost like a laser, to focus on the architecture without polluting the sky
- The result
- Clearly showcasing the height and grandeur of the villa
Common mistakeDouble-height ceilings and wasted luxury
“Got a double-height ceiling? Don't repeat the mistake that ruins the whole look of the living room!”
- The problem
- Using wide-angle (60°) spotlights in high ceilings, so the light scatters in the air and never reaches the floor.
- Technical explanation
- Ceilings 6 to 7 m high need a narrow Beam Angle of 15° or less.
- The result
- Light reaches the floor with a dramatic effect that conveys luxury and avoids wasted light.