Quick answer: Most halo letters sit 25–40 mm off the wall. Less than 20 mm gives a hard, narrow glow; more than 50 mm spreads the light but weakens it and increases wind load. The right number depends on letter size, LED output and wall texture.
What standoff does
A halo letter throws light backwards onto the wall. The distance between the letter and the wall controls the width of the glow: close means a tight bright outline, far means a softer wider halo. It also controls how much the letter itself is silhouetted.
Rule-of-thumb by letter size
- Small letters under 300 mm — 15–25 mm
- 300–800 mm — 25–40 mm
- Over 800 mm — 40–60 mm, confirmed with a mock-up
These are starting points. A high-output module at 15 mm can look harsher than a lower-output module at 30 mm.
Wall texture matters
A smooth painted wall reflects a clean halo. Brick, stone or ribbed cladding breaks the glow into a pattern, which can look intentional or messy depending on the design. On textured walls, increase the standoff slightly and use a wider diffuser so the pattern reads as texture rather than stripes.
Wind and structure
Longer standoffs increase the lever arm on the fixings. On exposed facades, specify a deeper return or a stronger bracket rather than simply adding spacers. The mounting rules are covered in wind load and mounting.
Colour temperature and standoff together
Warm white at a close standoff reads as a tight golden outline; cool white at a wider standoff reads as a soft blue wash. Test the combination rather than choosing them separately. Colour selection is covered in the reverse lit design guide.
Related reading: how far halo letters should sit from the wall.
Related reading: why halo letters look uneven.